Electrical and Optical Characterization of Surface Passivation in GaAs Nanowires

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• 作者：Chia-Chi Chang ; Chun-Yung Chi ; Maoqing Yao ; Ningfeng Huang ; Chun-Chung Chen ; Jesse Theiss ; Adam W. Bushmaker ; Stephen LaLumondiere ; Ting-Wei Yeh ; Michelle L. Povinelli ; Chongwu Zhou ; P. Daniel Dapkus ; Stephen B. Cronin
• 刊名：Nano Letters
• 出版年：2012
• 出版时间：September 12, 2012
• 年：2012
• 卷：12
• 期：9
• 页码：4484-4489
• 全文大小：316K
• 年卷期：v.12,no.9(September 12, 2012)
• ISSN：1530-6992

文摘

We report a systematic study of carrier dynamics in Al_xGa_1鈥?i>xAs-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_xGa_1鈥?i>xAs 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 脳 10³ to 1.1 脳 10⁴ cm路s^鈥?, and the minority carrier mobility 渭 is estimated to lie in the range from 10.3 to 67.5 cm² V^鈥? s^鈥? for the passivated nanowires.

Keywords:

MOCVD; EBIC; TR-PL; GaAs; surface passivation; selective area growth