Single InAs Nanowire Room-Temperature Near-Infrared Photodetectors

• Published in: ACS nano Vol. 8; no. 4; pp. 3628 - 3635
• Main Authors: Miao, Jinshui, Hu, Weida, Guo, Nan, Lu, Zhenyu, Zou, Xuming, Liao, Lei, Shi, Suixing, Chen, Pingping, Fan, Zhiyong, Ho, Johnny C, Li, Tian-Xin, Chen, Xiao Shuang, Lu, Wei
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 22.04.2014
• Subjects: Atmospherics; Detectors; Hafnium oxide; Indium arsenides; Nanowires; Photodetectors; Photoelectric effect; Surface defects; half-wrapped top-gate; surface defect states; photoresponsivity; infrared photodetectors; InAs nanowire
• ISSN: 1936-0851; 1936-086X
• DOI: 10.1021/nn500201g

Here we report InAs nanowire (NW) near-infrared photodetectors having a detection wavelength up to ∼1.5 μm. The single InAs NW photodetectors displayed minimum hysteresis with a high I on/I off ratio of 105. At room temperature, the Schottky–Ohmic contacted photodetectors had an external photoresponsivity of ∼5.3 × 103 AW–1, which is ∼300% larger than that of Ohmic–Ohmic contacted detectors (∼1.9 × 103 AW–1). A large enhancement in photoresponsivity (∼300%) had also been achieved in metal Au-cluster-decorated InAs NW photodetectors due to the formation of Schottky junctions at the InAs/Au cluster contacts. The photocurrent decreased when the photodetectors were exposed to ambient atmosphere because of the high surface electron concentration and rich surface defect states in InAs NWs. A theoretical model based on charge transfer and energy band change is proposed to explain this observed performance. To suppress the negative effects of surface defect states and atmospheric molecules, new InAs NW photodetectors with a half-wrapped top-gate had been fabricated by using 10 nm HfO2 as the top-gate dielectric.