www.advmat.de www.MaterialsViews.com
Wei Zheng, Feng Huang,* Ruisheng Zheng, and Honglei Wu Vacuum-ultraviolet (VUV) spectrum is located in the range of 10–200 nm.[1] Although VUV light cannot reach the ground surface, the high-sensitivity detection of VUV light is significant for coping space weather and monitoring hazardous,[2] such as the occurrence and variability of solar winds,[3,4] and contributes to the evolution of solar-terrestrial physics and geospace sciences.[5,6] At present, the mature VUV detection mostly draws support from satellite systems consisted of the Rowland spectrograph with microchannel plate detector.[6,7] Such instruments, requiring thousands of operating voltage, are huge and ponderous, thus not only increasing the working load of satellite but also running up the cost of launching. The best solution is to develop an ultrawide band gap (UWBG, Eg > 6.0 eV) semiconductor-based VUV photodetector, which is compact with low power-consumption and small size. However, it is far from reachable due to the lack of high quality UWBG semiconductor single crystal materials. Recently, low-dimensional nanostructure wide band gap (WBG, generally Eg in the range of 3–6 eV) semiconductor materials as building blocks for UV photodetectors has attracted intense attention.[1,8,9] Compared with traditional photodetectors based on thin-film and bulk structures, the nanostructured ones have higher responsivity and faster response speed, since the interior of nanostructures is usually defect-free,[10–12] and has high crystalline quality.[13,14] Besides, the low-dimensional conductive channel of nanostructures could confine the active area of charge carrier and shorten carrier transit time.[1,15–17] Typically, some WBG semiconductors with high quality, including ZnO,[18–20] ZnS,[21] GaN,[22,23] SnO2,[24] Nb2O5,[25] etc, have been applied to fabricate nanostructured photodetectors, showing high performance and potential application prospects in UV light detection. However, the reported photodetectors have a poor selectivity for VUV light, due to the band gaps Dr. W. Zheng, Prof. F. Huang State Key Laboratory of Optoelectronic Materials and Technologies School of Physics and Engineering Sun Yat-Sen University Guangzhou 510275, P. R. China E-mail:
[email protected] Prof. R. Zheng, Dr. H. Wu Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province Institute of Optoelectronics Shenzhen University Shenzhen 518060, P. R. China
DOI: 10.1002/adma.201500268
Adv. Mater. 2015, 27, 3921–3927
COMMUNICATION
Low-Dimensional Structure Vacuum-Ultraviolet-Sensitive (λ < 200 nm) Photodetector with Fast-Response Speed Based on High-Quality AlN Micro/Nanowire
of the utilized semiconductors are relatively narrow (
