Distinct photocurrent response of individual GaAs nanowires induced by n-type doping.
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 × 10(12) s(-1) for 2 × 10(17)cm(-3) 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.
National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, 500 YuTian Road, Shanghai 200083, People's Republic of China.
Hui
H
Xia
Zhen-Yu
ZY
Lu
Tian-Xin
TX
Li
Patrick
P
Parkinson
Zhi-Ming
ZM
Liao
Fu-Hao
FH
Liu
Wei
W
Lu
Wei-Da
WD
Hu
Ping-Ping
PP
Chen
Hong-Yi
HY
Xu
Jin
J
Zou
Chennupati
C
Jagadish