Distinct Photocurrent Response of Individual GaAs Nanowires Induced by n-Type Doping

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• 作者：Hui Xia ; Zhen-Yu Lu ; Tian-Xin Li ; Patrick Parkinson ; Zhi-Ming Liao ; Fu-Hao Liu ; Wei Lu ; Wei-Da Hu ; Ping-Ping Chen ; Hong-Yi Xu ; Jin Zou ; Chennupati Jagadish
• 刊名：ACS Nano
• 出版年：2012
• 出版时间：July 24, 2012
• 年：2012
• 卷：6
• 期：7
• 页码：6005-6013
• 全文大小：604K
• 年卷期：v.6,no.7(July 24, 2012)
• ISSN：1936-086X

文摘

The doping-dependent photoconductive properties of individual GaAs nanowires have been studied by conductive atomic force microscopy. Linear responsivity against the bias voltage is observed for moderate n-doped GaAs wires with a Schottky contact under illumination, while that of the undoped ones exhibits a saturated response. The carrier lifetime of a single nanowire can be obtained by simulating the characteristic photoelectric behavior. Consistent with the photoluminescence results, the significant drop of minority hole lifetime, from several hundred to subpicoseconds induced by n-type doping, leads to the distinct photoconductive features. Moreover, by comparing with the photoelectric behavior of AlGaAs shelled nanowires, the equivalent recombination rate of carriers at the surface is assessed to be >1 脳 10¹² s^鈥? for 2 脳 10¹⁷cm^鈥? n-doped bare nanowires, nearly 30 times higher than that of the doping-related bulk effects. This work suggests that intentional doping in nanowires could change the charge status of the surface states and impose significant impact on the electrical and photoelectrical performances of semiconductor nanostructures.

Keywords:

GaAs nanowire; photoconductive property; intentional doping; minority carrier lifetime; surface states; photoelectric device