Co-reporter:Dan-Dan Wang;Cai-Wang Ge;Guo-An Wu;Zhi-Peng Li;Jiu-Zhen Wang;Teng-Fei Zhang;Yong-Qiang Yu
Journal of Materials Chemistry C 2017 vol. 5(Issue 6) pp:1328-1335
Publication Date(Web):2017/02/09
DOI:10.1039/C6TC05117K
Plasmonic optoelectronic device based non-noble metal nanostructures (e.g. Al, In, etc.) have recently received increasing research interest due to their relatively low fabrication cost and tunable plasmon wavelength. In this study, we present a new plasmonic red light nano-photodetector by decorating a multi-layer graphene (MLG)–CdSe nanoribbon (CdSeNR) Schottky junction with a highly ordered plasmonic copper nanoparticle (CuNP) array, which exhibited obvious localized surface plasmon resonance in the range of 700–900 nm. Optoelectronic analysis reveals that the device metrics including the switch ratio, the responsivity and the detectivity considerably increased after functionalization with plasmonic CuNPs. Moreover, the response speed was fastened by nearly one order of magnitude. The observed optimization in device performance, according to theoretical simulations based on the finite element method (FEM) and experimental analysis, could be attributed to localized surface plasmon resonance (LSPR) induced hot electron injection. The above results signify that the present plasmonic CuNPs are equally important candidates for boosting the device performance of nano-optoelectronic devices.
Co-reporter:Feng-Xia Liang;Jiu-Zhen Wang;Zhi-Xiang Zhang;You-Yi Wang;Yang Gao
Advanced Optical Materials 2017 Volume 5(Issue 22) pp:
Publication Date(Web):2017/11/01
DOI:10.1002/adom.201700654
AbstractIn this study, a high-performance photodetector comprised of formamidinium cesium lead iodide (FA1−xCsxPbI3) thin film is developed. The Cs-doped FAPbI3 perovskite material is synthesized through a simple spin-coating method, via which FA1−xCsxPbI3 with different Cs doping levels (x = 0.1, 0.15, 0.2, and 0.3) can be obtained. Further optoelectronic characterization reveals that the FA0.85Cs0.15PbI3 photodetector exhibits reproducible sensitivity to irradiation with wavelengths in the range from 240 to 750 nm, whereas it is weakly sensitive to wavelengths longer than 750 nm. The responsivity and specific detectivity are estimated to be around 5.7 A W−1 and 2.7 × 1013 cm Hz1/2 W–1, respectively. It is also worth noting that the present perovskite photodetector demonstrates an ultrafast response speed (tr/tf: 45 ns/91 ns) at zero bias voltage, which is probably related to the ultrafast lifetime and high quality of thin film according to the Hall effect study. Finally, this device shows a weak degradation in sensitivity to white light after storage at ambient condition for 45 days. The totality of the broadband sensitivity, high specific detectivity, ultrafast response speed, and self-driven property renders the FA1−xCsxPbI3 an idea material for high-performance photodetectors application.
Co-reporter:Chun-Yan Wu;Zhi-Qiang Pan;Zhu Liu;You-Yi Wang
Journal of Nanoparticle Research 2017 Volume 19( Issue 2) pp:35
Publication Date(Web):18 January 2017
DOI:10.1007/s11051-016-3736-z
Face-centered cubic Cu2S nanowires with length of up to 50 μm and diameters in the range of 100–500 nm are synthesized on Si substrates through the chemical vapor deposition method using a mixed gas of Ar and H2 as the carrier gas under a chamber pressure of about 700 Torr. It was found that the growth of quasi 1D nanostructure followed a typical vapor-liquid-solid (VLS) mechanism in which the element Cu was reduced by H2 as the catalyst. The as-synthesized Cu2S nanowires exhibited typical p-type semiconducting characteristics with a conductivity of about 600 S cm−1 and a hole mobility (μh) of about 72 cm2 V−1 s−1. Further study reveals that p-Cu2S nanowires/n-Si heterojunction exhibits distinct rectifying characteristics with a turn-on voltage of ~0.6 V and a rectification ratio of ~300 at ±1 V in the dark and a pronounced photovoltaic behavior with an open circuit voltage (Voc) of 0.09 V and a short circuit current (Isc) of 65 nA when illuminated by the NIR light (790 nm, 0.35 mW cm−1), giving rise to a responsivity (R) about 0.8 mA W−1 and specific detectivity (D*) 6.7 × 1010 cm Hz1/2 W−1 at zero bias, which suggests the potential of as-synthesized Cu2S nanowires applied in the field of self-driven NIR photodetector.
Co-reporter:Chun-Yan Wu, Xin-Gang Wang, Zhi-Qiang Pan, You-Yi Wang, Yong-Qiang Yu, Li Wang and Lin-Bao Luo
Journal of Materials Chemistry A 2016 vol. 4(Issue 3) pp:589-595
Publication Date(Web):15 Dec 2015
DOI:10.1039/C5TC03829D
Tetragonal KCu7S4 nanobelts (NBs) with width of 200–600 nm and length of up to hundreds of micrometers were facially synthesized via a solution-based method. Electrical analysis reveals that the as-fabricated NB exhibits typical p-type semiconducting characteristics with an exceptionally high carrier mobility of ∼870 cm2 V−1 s−1, which may be attributed to the quasi-1D conduction path along the c axis in the structure of KCu7S4. A further study of a device based on the Cu/KCu7S4 NB/Au Schottky junction shows a stable memory behavior with a set voltage of about 0.6 V, a current ON/OFF ratio of about 104, and a retention time >104 s. Such resistive switching characteristics, according to our analysis are due to the interfacial oxide layers that can efficiently trap the electrons by the oxygen vacancies. This study will offer opportunities for the development of high-performance memory devices with new geometries.
Co-reporter:Zhongjun Li, Wei Xu, Yuanqin Yu, Hongyang Du, Kun Zhen, Jun Wang, Linbao Luo, Huaili Qiu and Xiaobao Yang
Journal of Materials Chemistry A 2016 vol. 4(Issue 2) pp:362-370
Publication Date(Web):01 Dec 2015
DOI:10.1039/C5TC03001C
Monolayer hexagonal arsenene (hAs), a typical two-dimensional semiconducting material with a wide band gap and high stability, has attracted increasing research interest due to its potential applications in optoelectronics. Using first-principles calculations, we have investigated the electronic and magnetic properties of x-substituted hAs (x = B, C, N, O, Ga, Ge, Se, and monovacancy) and x-adsorbed hAs (x = As). Our results show that the B-, N-, and Ga-substituted hAs have spin-unpolarized semiconducting characters like pristine hAs, and indirect–direct band gap transitions are induced in the B- and N-substituted systems. In contrast, the O-, Se-, and monovacancy-substituted hAs are metallic, and the C- and Ge-substituted hAs show spin-polarized semiconducting characters with band gaps of 1.1 and 1.3 eV for the spin-up channels and 1.0 and 0.7 eV for the spin-down channels, respectively. For the As-adsorbed hAs, the Fermi level crosses the spin-up states, yielding metallic behavior, while the spin-down channel retains semiconducting character. Detailed analysis of electronic structures for the C-substituted, Ge-substituted, and As-adsorbed hAs shows that strong hybridizations between the doping atoms and As atoms lead to energy splitting near the Fermi level and consequently induce magnetic moments. By selective doping, hAs can be transformed from a spin-nonpolarized semiconductor to a spin-polarized semiconductor, to a half-metal, or even to a metal, which indicates that the doped hAs will have promising potential in future electronics, spintronics, and optoelectronics.
Co-reporter:Yuan Wang;Cai-Wang Ge;Yi-Feng Zou;Rui Lu;Kun Zheng;Teng-Fei Zhang;Yong-Qiang Yu
Advanced Optical Materials 2016 Volume 4( Issue 2) pp:291-296
Publication Date(Web):
DOI:10.1002/adom.201500360
Plasmonic nanostructures composed of poor metals (e.g., In, Cu, Al) have lately received increasing interest due to their low cost and natural abundance relative to noble metal nanoparticles (e.g., Au, Ag, Pt). To date, while considerable progress has been achieved with regard to the utilization of plasmonic noble metal nanostructures for optimizing various optoelectronic devices, little work has been performed to study the device appplication of poor metals. In this study, a high-performance blue light nano-photodetector is induced through the use of a highly ordered indium nanoparticle (InNP) array. Electrical analysis reveals that, after decoration with the plasmonic InNP array, the photocurrent of the nano-photodetector increases considerably, giving rise to an obvious increase in responsivity and gain. Such an increase in device performance, according to simulations based on the finite element method, is attributed to the plasmonic InNPs which can induce direct electron transfer from InNPs to ZnSe nanoribbons. This study suggests that poor metal nanoparticles are equally important candidates for boosting the device performance of light-harvesting optoelectronic devices.
Co-reporter:Lin-Bao Luo;Yi-Feng Zou;Cai-Wang Ge;Kun Zheng;Dan-Dan Wang;Rui Lu;Teng-Fei Zhang;Yong-Qiang Yu;Zhong-Yi Guo
Advanced Optical Materials 2016 Volume 4( Issue 5) pp:763-771
Publication Date(Web):
DOI:10.1002/adom.201500701
In this work, we present a plasmonic near infrared light photodetector for the detection of 980 nm illumination. The plasmonic photodetector is fabricated by modifying single layer graphene (SLG)/InP Schottky junction diode with SiO2 encapsulated gold nanorods (SiO2@AuNR), which can confine the incident NIR light by inducing obvious localized surface plasmon resonance, according to theoretical simulation based on finite element method. This study shows that after decoration with plasmonic SiO2@AuNR, the device performance in terms of photocurrent and responsivity is considerably enhanced. In addition, the device exhibited a very fast respose rate which is able to monitor switching optical signals with a frequency as high as 1 MHz, suggesting a potential application for sensing high-frequency optical signals. This study manifests that the present plasmonic NIR photodetector will have great potential in future optoelectronic devices application.
Co-reporter:Caiwang Ge, Zhongyi Guo, Yongxuan Sun, Fei Shen, Yifei Tao, Jingran Zhang, Rongzhen Li, Linbao Luo
Optics Communications 2016 Volume 359() pp:393-398
Publication Date(Web):15 January 2016
DOI:10.1016/j.optcom.2015.10.005
•We present a metal nanoslit arrays structure, which can offer a wideband (550–1200 nm) detection.•We have investigated the sensor response upon molecular adsorping at different positions.•When a BSA protein on slit walls, the shifts can reach to more than 80 nm at W=5nm.A novel spatial and spectral selective plasmonic sensing based on the metal nanoslit arrays has been proposed and investigated theoretically, which shows a high performance in the multiplexing biomolecular detections. By properly tuning the geometric parameters of metal nanoslit arrays, the enhanced optical fields at different regions can be obtained selectively due to the excitation of SPP, cavity mode (CM), and their coupling effects. Simulation results show that the resonances of the metal nanoslit arrays at different spatial locations and different wavelengths can be achieved simultaneously. A relative bigger red-shift of 57 nm can be realized when a layer of biomolecular film is adsorbing at the slit walls, and the corresponding total intensity difference will be enhanced near 10 times compared to that at the top surface. In addition, when a BSA protein monolayer is adsorbing at slit walls with different slit widths, the corresponding wavelength shifts can reach to more than 80 nm by modulating the widths of the slit. The simulated results demonstrate that our designed metal nanoslit arrays can serve as a portable, low-cost biosensing with a high spatial and spectral selective performance.
Co-reporter:Kun Zheng, Lin-Bao Luo, Teng-Fei Zhang, Yu-Hung Liu, Yong-Qiang Yu, Rui Lu, Huai-Li Qiu, Zhong-Jun Li and J. C. Andrew Huang
Journal of Materials Chemistry A 2015 vol. 3(Issue 35) pp:9154-9160
Publication Date(Web):04 Aug 2015
DOI:10.1039/C5TC01772F
In this study, we present a near infrared (NIR) light photodetector based on a topological insulator antimony telluride (Sb2Te3) film, which was grown on sapphire by molecular beam epitaxy (MBE). Electrical analysis reveals that the resistance of the topological insulator decreases with increasing temperature in the temperature range of 8.5–300 K. Further optoelectronic characterization showed that the as-fabricated photodetector exhibits obvious sensitivity to 980 nm light illumination. The responsivity, photoconductive gain and detectivity were estimated to be 21.7 A/W, 27.4 and 1.22 × 1011 Jones, respectively, which are much better than those of other topological insulators based devices. This study suggests that the present NIR photodetector may have potential application in future optoelectronic devices.
Co-reporter:Li Wang, Hong-Wei Song, Zhen-Xing Liu, Xu Ma, Ran Chen, Yong-Qiang Yu, Chun-Yan Wu, Ji-Gang Hu, Yan Zhang, Qiang Li and Lin-Bao Luo
Journal of Materials Chemistry A 2015 vol. 3(Issue 12) pp:2933-2939
Publication Date(Web):03 Feb 2015
DOI:10.1039/C4TC02943G
In this study, we reported on the construction of p–n junctions based on crystalline Ga-doped CdS–polycrystalline ZnTe nanostructures (NSs) for optoelectronic device application. The coaxial nano-heterojunction was fabricated by a two-step growth method. It is found that the absorption edge of CdS:Ga–ZnTe:Sb core–shell NSs red shifted to about 580 nm, compared with CdS nanowires (520 nm). The as-fabricated core–shell p–n junction exhibited obvious rectification characteristics with a low turn-on voltage of ∼0.25 V. What is more, it showed stable and repeatable photoresponse to 638 nm light illumination, with a responsivity and a detectivity of 1.55 × 103 A W−1 and 8.7 × 1013 cm Hz1/2 W−1, respectively, much higher than other photodetectors with similar device configurations. The generality of this study suggests that the present coaxial CdS:Ga–ZnTe:Sb core–shell nano-heterojunction will have great potential applications in future nano-optoelectronic devices.
Co-reporter:Feng-Xia Liang, Deng-Yue Zhang, Yi-feng Zou, Han Hu, Teng-Fei Zhang, Yu-Cheng Wu and Lin-Bao Luo
RSC Advances 2015 vol. 5(Issue 25) pp:19020-19026
Publication Date(Web):09 Feb 2015
DOI:10.1039/C4RA16781C
In this study, we present a simple oxide assisted p-type doping of Si nanostructures by evaporating a mixed powder composed of SiB6 and SiO. It was found that Si nanoribbons (Si NRs) which can be obtained at high SiB6 content, will give way to Si nanowires (Si NWs) when the content of SiB6 in the mixed powder was reduced. According to our transport measurement of field effect transistors (FETs) assembled on individual Si nanostructures, the as-prepared Si nanostructures with different boron doping levels all exhibit typical p-type conduction characteristics. Additionally, the electrical conductivity of the Si nanostructures can be tuned over 7 orders of magnitude from 8.98 × 102 S cm−1 for the highly doped sample to 3.36 × 10−5 S cm−1 for the lightly doped sample. We also assembled a nano-photodetector based on monolayer graphene and the as-prepared Si nanostructures, which exhibits ultra-sensitivity to 850 nm near infrared light (NIR) illumination with a nanosecond response speed (τrise/τfall: 181/233 ns). The generality of the above results suggest that the Si nanostructures are promising building blocks for future electronic and optoelectronic device applications.
Co-reporter:Lin-Bao Luo, Shun-Hang Zhang, Rui Lu, Wei Sun, Qun-Ling Fang, Chun-Yan Wu, Ji-Gang Hu and Li Wang
RSC Advances 2015 vol. 5(Issue 18) pp:13324-13330
Publication Date(Web):19 Jan 2015
DOI:10.1039/C4RA14096F
Although significant progress has been achieved in the synthesis and doping of ZnTe nanostructures, it remains a major challenge to rationally tune their transport properties for nanodevice applications. In this work, p-type ZnTe nanowires (NWs) with tunable conductivity were synthesized by employing Ga/Ga2O3 as a dopant via a simple thermal evaporation method. Electrical measurements of back-gate metal-oxide field-effect-transistors based on a single NW revealed that when the Ga content in the ZnTe NWs increases from 1.3 to 5.1 and 8.7%, the hole mobility and hole concentration will increase from 0.0069 to 0.33 to 0.46 cm2 V−1 s−1, respectively. It was also found that the photodetector composed of a ZnTe:Ga NW/graphene Schottky diode exhibited high sensitivity to visible light illumination with an on/off ratio as high as 102 at reverse bias, with good reproducibility. The responsivity and detectivity were estimated to be 4.17 × 103 A W−1 and 3.19 × 1013 cm Hz1/2 W−1, higher than other ZnTe nanostructure based photodetectors. It is expected that the ZnTe:Ga NWs with controlled p-type conductivity are promising building blocks for fabricating high performance nano-optoelectronic devices in the future.
Co-reporter:Yong-Qiang Yu;Ming-Zheng Wang;Bo Wang;Long-Hui Zeng
Nano Research 2015 Volume 8( Issue 4) pp:1098-1107
Publication Date(Web):2015 April
DOI:10.1007/s12274-014-0587-8
We present an ultrasensitive ultraviolet (UV) detector based on a p-type ZnS nanoribbon (NR)/indium tin oxide (ITO) Schottky barrier diode (SBD). The device exhibits a pseudo-photovoltaic behavior which can allow the SBD to detect UV light irradiation with incident power of 6 × 10−17 W (∼85 photons/s on the NR) at room temperature, with excellent reproducibility and stability. The corresponding detectivity and photoconductive gain are calculated to be 3.1 × 1020 cm·Hz1/2·W−1 and 6.6 × 105, respectively. It is found that the presence of the trapping states at the p-ZnS NR/ITO interface plays a crucial role in determining the ultrahigh sensitivity of this nanoSBDs. Based on our theoretical calculation, even ultra-low photon fluxes on the order of several tens of photons could induce a significant change in interface potential and consequently cause a large photocurrent variation. The present study provides new opportunities for developing high-performance optoelectronic devices in the future.
Co-reporter:Lin-Bao Luo;Jing-Jing Chen;Ming-Zheng Wang;Han Hu;Chun-Yan Wu;Qiang Li;Li Wang;Jian-An Huang;Feng-Xia Liang
Advanced Functional Materials 2014 Volume 24( Issue 19) pp:2794-2800
Publication Date(Web):
DOI:10.1002/adfm.201303368
Near infrared light photodiodes have been attracting increasing research interest due to their wide application in various fields. In this study, the fabrication of a new n-type GaAs nanocone (GaAsNCs) array/monolayer graphene (MLG) Schottky junction is reported for NIR light detection. The NIR photodetector (NIRPD) shows obvious rectifying behavior with a turn-on voltage of 0.6 V. Further device analysis reveals that the photovoltaic NIRPDs are highly sensitive to 850 nm light illumination, with a fast response speed and good spectral selectivity at zero bias voltage. It is also revealed that the NIRPD is capable of monitoring high-switching frequency optical signals (∼2000 Hz) with a high relative balance. Theoretical simulations based on finite difference time domain (FDTD) analysis finds that the high device performance is partially associated with the optical property, which can trap most incident photons in an efficient way. It is expected that such a self-driven NIRPD will have potential application in future optoelectronic devices.
Co-reporter:Lin-Bao Luo, Chao Xie, Xian-He Wang, Yong-Qiang Yu, Chun-Yan Wu, Han Hu, Ke-Ya Zhou, Xi-Wei Zhang, Jian-Sheng Jie
Nano Energy 2014 Volume 9() pp:112-120
Publication Date(Web):October 2014
DOI:10.1016/j.nanoen.2014.07.003
•The power conversion efficiency of the device is increased from 6.39% to 10.15%.•Plasmonic Au nanoparticles are capable of trapping light.•Au nanoparticles are responsible for the enhancement of optical absorption of the Si.•The solar cell exhibits good air stability and excellent reproducibility.Metal nanoparticles (NPs) induced surface plasmon resonance (SPR) is of great interest for efficient controlling over light׳s propagation and absorption in optoelectronic devices applications. In this work, we proposed a simple strategy to improve the photocurrent of planar silicon (Si) p–n junction solar cells by attaching plasmonic Au nanoparticles (AuNPs) onto transparent graphene film to enhance incident light harvesting. Finite Element Method based simulations reveal that the strong light scattering by AuNPs is responsible for the optical absorption enhancement within Si, leading to the increase in photocurrent. In addition, decoration of AuNPs on graphene also contributes to a high fill factor (FF) by reducing series resistance in the circuit. These contributory factors, together with the effective surface passivation of Si yield a power conversion efficiency (PCE) as high as 10.15%, with excellent reproducibility. This study will open up new opportunities for the optimization of Si based optoelectronic devices.
Co-reporter:Chao Xie, Biao Nie, Longhui Zeng, Feng-Xia Liang, Ming-Zheng Wang, Linbao Luo, Mei Feng, Yongqiang Yu, Chun-Yan Wu, Yucheng Wu, and Shu-Hong Yu
ACS Nano 2014 Volume 8(Issue 4) pp:4015
Publication Date(Web):March 26, 2014
DOI:10.1021/nn501001j
Silicon nanostructure-based solar cells have lately intrigued intensive interest because of their promising potential in next-generation solar energy conversion devices. Herein, we report a silicon nanowire (SiNW) array/carbon quantum dot (CQD) core–shell heterojunction photovoltaic device by directly coating Ag-assisted chemical-etched SiNW arrays with CQDs. The heterojunction with a barrier height of 0.75 eV exhibited excellent rectifying behavior with a rectification ratio of 103 at ±0.8 V in the dark and power conversion efficiency (PCE) as high as 9.10% under AM 1.5G irradiation. It is believed that such a high PCE comes from the improved optical absorption as well as the optimized carrier transfer and collection capability. Furthermore, the heterojunction could function as a high-performance self-driven visible light photodetector operating in a wide switching wavelength with good stability, high sensitivity, and fast response speed. It is expected that the present SiNW array/CQD core–shell heterojunction device could find potential applications in future high-performance optoelectronic devices.Keywords: barrier height; carbon quantum dots; relative balance; silicon nanowire array; surface passivation
Co-reporter:Fang-Ze Li;Qing-Dan Yang;Di Wu;Chao Xie;Biao Nie;Jian-Sheng Jie;Chun-Yan Wu;Li Wang;Shu-Hong Yu
Advanced Energy Materials 2013 Volume 3( Issue 5) pp:579-583
Publication Date(Web):
DOI:10.1002/aenm.201200868
Co-reporter:Long-Hui Zeng, Ming-Zheng Wang, Han Hu, Biao Nie, Yong-Qiang Yu, Chun-Yan Wu, Li Wang, Ji-Gang Hu, Chao Xie, Feng-Xia Liang, and Lin-Bao Luo
ACS Applied Materials & Interfaces 2013 Volume 5(Issue 19) pp:9362
Publication Date(Web):September 16, 2013
DOI:10.1021/am4026505
We report on the simple fabrication of monolayer graphene (MLG)/germanium (Ge) heterojunction for infrared (IR) light sensing. It is found that the as-fabricated Schottky junction detector exhibits obvious photovoltaic characteristics, and is sensitive to IR light with high Ilight/Idark ratio of 2 × 104 at zero bias voltage. The responsivity and detectivity are as high as 51.8 mA W–1 and 1.38 × 1010 cm Hz1/2 W–1, respectively. Further photoresponse study reveals that the photovoltaic IR detector displays excellent spectral selectivity with peak sensitivity at 1400 nm, and a fast light response speed of microsecond rise/fall time with good reproducibility and long-term stability. The generality of the above results suggests that the present MLG/Ge IR photodetector would have great potential for future optoelectronic device applications.Keywords: heterojunction; infrared photodetector; photovoltaic effect; response speed; Schottky junction;
Co-reporter:Di Wu, Yang Jiang, Yugang Zhang, Yongqiang Yu, Zhifeng Zhu, Xinzheng Lan, Fangze Li, Chunyan Wu, Li Wang and Linbao Luo
Journal of Materials Chemistry A 2012 vol. 22(Issue 43) pp:23272-23276
Publication Date(Web):08 Oct 2012
DOI:10.1039/C2JM34869A
Self-powered photodetectors based on CdS:Ga nanoribbons (NR)/Au Schottky barrier diodes (SBDs) were fabricated. The as-fabricated SBDs exhibit an excellent rectification characteristic with a rectification ratio up to 106 within ±1 V in the dark and a distinctive photovoltaic (PV) behavior under light illumination. Photoconductive analysis reveals that the SBDs were highly sensitive to light illumination with very good stability, reproducibility and fast response speeds at zero bias voltage. The corresponding rise/fall times of 95/290 μs represent the best values obtained for CdS based nano-photodetectors. It is expected that such self-powered high performance SBD photodetectors will have great potential applications in optoelectronic devices in the future.
Co-reporter:Lin-Bao Luo, Xiao-Bao Yang, Feng-Xia Liang, Jian-Sheng Jie, Qiang Li, Zhi-Feng Zhu, Chun-Yan Wu, Yong-Qiang Yu and Li Wang
CrystEngComm 2012 vol. 14(Issue 6) pp:1942-1947
Publication Date(Web):23 Jan 2012
DOI:10.1039/C2CE06420K
We report a synthesis of single-crystal [001] oriented selenium nanobelts (SeNBs) through a simple vacuum evaporation at 250 °C. The width and thickness of the SeNBs are in the range of 100–800 nm and 20–90 nm, respectively. I–V analysis of an individual SeNB based field effect transistor (FET) reveals typical p-type electrical conduction. The hole mobility and concentration are respectively estimated to 0.63 cm2 (V s)−1 and 9.35 × 1016 cm−3. The p-type electrical characteristics can be explained by the surface termination model, according to which, H- or OH- termination can induce a defect level slightly above the valance band maximum (VBM). A fully transparent and flexible visible light photodetector assembled on a polyethylene terephthalate (PET) substrate shows a high sensitivity to visible light illumination, with sensitivity and conductive gain as high as 3.27 × 104 A W−1 and 6.77 × 104 respectively. Furthermore, the device also exhibits a stable performance and good reproducibility under different bending conditions. The high-performance visible light photodetector would enable application opportunities in future flexible and transparent electronics.
Co-reporter:Lin-Bao Luo, Tsz-Wai Ng, Hao Tang, Feng-Xia Liang, Yu-Cheng Dong, Jian-Sheng Jie, Chun-Yan Wu, Li Wang, Zhi-Feng Zhu, Yong-Qiang Yu and Qiang Li
RSC Advances 2012 vol. 2(Issue 8) pp:3361-3366
Publication Date(Web):02 Feb 2012
DOI:10.1039/C2RA01269C
We report on the surface transfer p-type doping of germanium nanowires (GeNWs) via MoO3 thin film deposition. The GeNWs studied were prepared by a conventional thermal evaporation approach. Electrical property analysis shows that the conductance, hole mobility and concentration were all prominently enhanced after MoO3 thin film coating. Such a remarkable surface doping effect can be attributed to the surface charge transfer at the GeNWs/MoO3 interface, which is verified by in situ XPS analysis of GeNWs as a function of increasing MoO3 coverage. Further hole mobility and concentration evolution study of MoO3/GeNWs reveals that the GeNWs embedded in the MoO3 layer can retain their electrical property after storage in air for 3 months. The generality of the above results suggests that the charge transfer doping via surface deposition has great potential in GeNW-based nanoelectronic devices and may also be applicable to the modulation of other semiconductor nanostructures.
Co-reporter:Yi Si Feng, Jing Jing Ma, Xin Yan Lin, Jia Song Zhang, Peng Lv, Hua Jian Xu, Lin Bao Luo
Chinese Chemical Letters 2012 Volume 23(Issue 12) pp:1411-1414
Publication Date(Web):December 2012
DOI:10.1016/j.cclet.2012.10.009
Graphene/acridine (G-Acr) hybrid structures were synthesized through covalent functionalization of graphene oxide with 9-(4-aminophenyl)acridine (APA) and its derivatives. The G-Acr hybrids were characterized by Fourier transform infrared spectroscopy, ultraviolet–visible spectrophotometry, thermal gravimetric analysis and Raman spectroscopy. X-ray photoelectron spectroscopy confirms that the binding energies of APA and its derivatives shifted to higher values, revealing pronounced charge transfer at the interface of graphene and organic molecules.
Co-reporter:Lin-Bao Luo;Feng-Xia Liang;Xiao-Li Huang
Journal of Nanoparticle Research 2012 Volume 14( Issue 6) pp:
Publication Date(Web):2012 June
DOI:10.1007/s11051-012-0967-5
We presented an attempt to modulate the electrical property of tellurium nanowires (TeNWs) via a surface charge transfer doping method. The TeNWs with length of several tens of micrometers and diameters of 20–50 nm were prepared by a simple hydrothermal method at 160 °C for 20 h. High-resolution transmission electron microscope image combined with selected area electron diffraction pattern shows the single-crystal nature and a growth direction along [001]. Electrical analysis of the individual TeNW-based field effect transistor before and after surface coating reveals that MoO3 and CuPc thin layer coating can greatly enhance both electrical conductivities and hole concentrations. Such a surface hole injection effect, according to the band energy alignment, can be attributed to the huge differences in work functions between TeNW and MoO3/CuPc. Furthermore, the influence of the deposited layer on carrier mobility is strikingly different, which is believed to be due to the discrepancy in surface scattering upon surface coating. The results from this study provide an effective alternative for doping other semiconductor nanostructures.
Co-reporter:Lin-bao Luo ; Xiao-bao Yang ; Feng-xia Liang ; Jian-sheng Jie ; Chun-yan Wu ; Li Wang ; Yong-qiang Yu ;Zhi-feng Zhu
The Journal of Physical Chemistry C 2011 Volume 115(Issue 49) pp:24293-24299
Publication Date(Web):October 31, 2011
DOI:10.1021/jp208708e
We report on the controllable doping of germanium nanowires (GeNWs) via selective molecule adsorption on the surface dangling bond. The GeNWs investigated are fabricated by evaporating pure germanium powder. Electron spin resonance analysis shows the presence of a surface dangling bond with g value of 2.023 and a spin density of Cspin = 2.47 × 1013 mg–1. The as-prepared undoped GeNW exhibits typical p-type conduction behavior in air but n-type electrical characteristics in ammonia atmosphere. Significantly, the conductance, carrier mobility, and concentrations are found to be highly dependent on vacuum and ammonia gas pressures. Such an ambient effect could be explained by a surface dangling bond-mediated molecule doping model, according to which an acceptor or donor level is formed by water or ammonia adsorption, respectively. The generality of the above results suggests that surface dangling bond-mediated molecule doping may be applicable to modulation of the electrical characteristics of other semiconductor nanostructures.
Co-reporter:Di Wu, Yang Jiang, Yugang Zhang, Yongqiang Yu, Zhifeng Zhu, Xinzheng Lan, Fangze Li, Chunyan Wu, Li Wang and Linbao Luo
Journal of Materials Chemistry A 2012 - vol. 22(Issue 43) pp:NaN23276-23276
Publication Date(Web):2012/10/08
DOI:10.1039/C2JM34869A
Self-powered photodetectors based on CdS:Ga nanoribbons (NR)/Au Schottky barrier diodes (SBDs) were fabricated. The as-fabricated SBDs exhibit an excellent rectification characteristic with a rectification ratio up to 106 within ±1 V in the dark and a distinctive photovoltaic (PV) behavior under light illumination. Photoconductive analysis reveals that the SBDs were highly sensitive to light illumination with very good stability, reproducibility and fast response speeds at zero bias voltage. The corresponding rise/fall times of 95/290 μs represent the best values obtained for CdS based nano-photodetectors. It is expected that such self-powered high performance SBD photodetectors will have great potential applications in optoelectronic devices in the future.
Co-reporter:Chun-Yan Wu, Xin-Gang Wang, Zhi-Qiang Pan, You-Yi Wang, Yong-Qiang Yu, Li Wang and Lin-Bao Luo
Journal of Materials Chemistry A 2016 - vol. 4(Issue 3) pp:NaN595-595
Publication Date(Web):2015/12/15
DOI:10.1039/C5TC03829D
Tetragonal KCu7S4 nanobelts (NBs) with width of 200–600 nm and length of up to hundreds of micrometers were facially synthesized via a solution-based method. Electrical analysis reveals that the as-fabricated NB exhibits typical p-type semiconducting characteristics with an exceptionally high carrier mobility of ∼870 cm2 V−1 s−1, which may be attributed to the quasi-1D conduction path along the c axis in the structure of KCu7S4. A further study of a device based on the Cu/KCu7S4 NB/Au Schottky junction shows a stable memory behavior with a set voltage of about 0.6 V, a current ON/OFF ratio of about 104, and a retention time >104 s. Such resistive switching characteristics, according to our analysis are due to the interfacial oxide layers that can efficiently trap the electrons by the oxygen vacancies. This study will offer opportunities for the development of high-performance memory devices with new geometries.
Co-reporter:Dan-Dan Wang, Cai-Wang Ge, Guo-An Wu, Zhi-Peng Li, Jiu-Zhen Wang, Teng-Fei Zhang, Yong-Qiang Yu and Lin-Bao Luo
Journal of Materials Chemistry A 2017 - vol. 5(Issue 6) pp:NaN1335-1335
Publication Date(Web):2016/12/21
DOI:10.1039/C6TC05117K
Plasmonic optoelectronic device based non-noble metal nanostructures (e.g. Al, In, etc.) have recently received increasing research interest due to their relatively low fabrication cost and tunable plasmon wavelength. In this study, we present a new plasmonic red light nano-photodetector by decorating a multi-layer graphene (MLG)–CdSe nanoribbon (CdSeNR) Schottky junction with a highly ordered plasmonic copper nanoparticle (CuNP) array, which exhibited obvious localized surface plasmon resonance in the range of 700–900 nm. Optoelectronic analysis reveals that the device metrics including the switch ratio, the responsivity and the detectivity considerably increased after functionalization with plasmonic CuNPs. Moreover, the response speed was fastened by nearly one order of magnitude. The observed optimization in device performance, according to theoretical simulations based on the finite element method (FEM) and experimental analysis, could be attributed to localized surface plasmon resonance (LSPR) induced hot electron injection. The above results signify that the present plasmonic CuNPs are equally important candidates for boosting the device performance of nano-optoelectronic devices.
Co-reporter:Kun Zheng, Lin-Bao Luo, Teng-Fei Zhang, Yu-Hung Liu, Yong-Qiang Yu, Rui Lu, Huai-Li Qiu, Zhong-Jun Li and J. C. Andrew Huang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 35) pp:NaN9160-9160
Publication Date(Web):2015/08/04
DOI:10.1039/C5TC01772F
In this study, we present a near infrared (NIR) light photodetector based on a topological insulator antimony telluride (Sb2Te3) film, which was grown on sapphire by molecular beam epitaxy (MBE). Electrical analysis reveals that the resistance of the topological insulator decreases with increasing temperature in the temperature range of 8.5–300 K. Further optoelectronic characterization showed that the as-fabricated photodetector exhibits obvious sensitivity to 980 nm light illumination. The responsivity, photoconductive gain and detectivity were estimated to be 21.7 A/W, 27.4 and 1.22 × 1011 Jones, respectively, which are much better than those of other topological insulators based devices. This study suggests that the present NIR photodetector may have potential application in future optoelectronic devices.
Co-reporter:Li Wang, Hong-Wei Song, Zhen-Xing Liu, Xu Ma, Ran Chen, Yong-Qiang Yu, Chun-Yan Wu, Ji-Gang Hu, Yan Zhang, Qiang Li and Lin-Bao Luo
Journal of Materials Chemistry A 2015 - vol. 3(Issue 12) pp:NaN2939-2939
Publication Date(Web):2015/02/03
DOI:10.1039/C4TC02943G
In this study, we reported on the construction of p–n junctions based on crystalline Ga-doped CdS–polycrystalline ZnTe nanostructures (NSs) for optoelectronic device application. The coaxial nano-heterojunction was fabricated by a two-step growth method. It is found that the absorption edge of CdS:Ga–ZnTe:Sb core–shell NSs red shifted to about 580 nm, compared with CdS nanowires (520 nm). The as-fabricated core–shell p–n junction exhibited obvious rectification characteristics with a low turn-on voltage of ∼0.25 V. What is more, it showed stable and repeatable photoresponse to 638 nm light illumination, with a responsivity and a detectivity of 1.55 × 103 A W−1 and 8.7 × 1013 cm Hz1/2 W−1, respectively, much higher than other photodetectors with similar device configurations. The generality of this study suggests that the present coaxial CdS:Ga–ZnTe:Sb core–shell nano-heterojunction will have great potential applications in future nano-optoelectronic devices.
Co-reporter:Zhongjun Li, Wei Xu, Yuanqin Yu, Hongyang Du, Kun Zhen, Jun Wang, Linbao Luo, Huaili Qiu and Xiaobao Yang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 2) pp:NaN370-370
Publication Date(Web):2015/12/01
DOI:10.1039/C5TC03001C
Monolayer hexagonal arsenene (hAs), a typical two-dimensional semiconducting material with a wide band gap and high stability, has attracted increasing research interest due to its potential applications in optoelectronics. Using first-principles calculations, we have investigated the electronic and magnetic properties of x-substituted hAs (x = B, C, N, O, Ga, Ge, Se, and monovacancy) and x-adsorbed hAs (x = As). Our results show that the B-, N-, and Ga-substituted hAs have spin-unpolarized semiconducting characters like pristine hAs, and indirect–direct band gap transitions are induced in the B- and N-substituted systems. In contrast, the O-, Se-, and monovacancy-substituted hAs are metallic, and the C- and Ge-substituted hAs show spin-polarized semiconducting characters with band gaps of 1.1 and 1.3 eV for the spin-up channels and 1.0 and 0.7 eV for the spin-down channels, respectively. For the As-adsorbed hAs, the Fermi level crosses the spin-up states, yielding metallic behavior, while the spin-down channel retains semiconducting character. Detailed analysis of electronic structures for the C-substituted, Ge-substituted, and As-adsorbed hAs shows that strong hybridizations between the doping atoms and As atoms lead to energy splitting near the Fermi level and consequently induce magnetic moments. By selective doping, hAs can be transformed from a spin-nonpolarized semiconductor to a spin-polarized semiconductor, to a half-metal, or even to a metal, which indicates that the doped hAs will have promising potential in future electronics, spintronics, and optoelectronics.
Co-reporter:Chun-Yan Wu, Zhi-Qiang Pan, You-Yi Wang, Cai-Wang Ge, Yong-Qiang Yu, Ji-Yu Xu, Li Wang and Lin-Bao Luo
Journal of Materials Chemistry A 2016 - vol. 4(Issue 46) pp:NaN10811-10811
Publication Date(Web):2016/10/27
DOI:10.1039/C6TC03856E
A highly sensitive near infrared light (NIR) photodetector was fabricated by coating a thin layer of Cu film onto a vertical n-type SiNW array through a solution based reduction reaction. The as-fabricated core–shell SiNW array/Cu Schottky junction exhibits an obvious rectifying behavior in the dark with a turn-on voltage of ∼0.5 V and a rectification ratio of about 102 at ±1.5 V. In addition, it shows a pronounced photovoltaic performance when illuminated by NIR light with a wavelength of 980 nm. Such photovoltaic characteristics can allow the device to detect NIR illumination without exterior power supply. Further device analysis reveals that the self-powered NIR photodetector is capable of monitoring ultrafast optical signals with a frequency as high as 30 kHz. What is more, the present device also has obvious advantages of high responsivity, detectivity, on/off ratio, and response speed. Further theoretical simulation reveals that the good device performance is associated with excellent optical and electrical properties of core–shell heterojunction geometry.
