Electrical and optical characterization of surface passivation in GaAs nanowires.
We report a systematic study of carrier dynamics in Al(x)Ga(1-x)As-passivated GaAs nanowires. With passivation, the minority carrier diffusion length (L(diff)) increases from 30 to 180 nm, as measured by electron beam induced current (EBIC) mapping, and the photoluminescence (PL) lifetime increases from sub-60 ps to 1.3 ns. A 48-fold enhancement in the continuous-wave PL intensity is observed on the same individual nanowire with and without the Al(x)Ga(1-x)As passivation layer, indicating a significant reduction in surface recombination. These results indicate that, in passivated nanowires, the minority carrier lifetime is not limited by twin stacking faults. From the PL lifetime and minority carrier diffusion length, we estimate the surface recombination velocity (SRV) to range from 1.7 × 10(3) to 1.1 × 10(4) cm·s(-1), and the minority carrier mobility μ is estimated to lie in the range from 10.3 to 67.5 cm(2) V(-1) s(-1) for the passivated nanowires.
Department of Physics, University of Southern California, Los Angeles, California 90089, United States.
Chia-Chi
CC
Chang
Chun-Yung
CY
Chi
Maoqing
M
Yao
Ningfeng
N
Huang
Chun-Chung
CC
Chen
Jesse
J
Theiss
Adam W
AW
Bushmaker
Stephen
S
Lalumondiere
Ting-Wei
TW
Yeh
Michelle L
ML
Povinelli
Chongwu
C
Zhou
P Daniel
PD
Dapkus
Stephen B
SB
Cronin
D001152:Arsenicals / Q000737:chemistry*; D004553:Electric Conductivity; D004579:Electron Transport; D005708:Gallium / Q000737:chemistry*; D008422:Materials Testing; D043942:Nanotubes / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D012031:Refractometry; D013499:Surface Properties
D001152:Arsenicals; C043055:gallium arsenide; D005708:Gallium