Carrier dynamics and doping profiles in GaAs nanosheets  

作　　者：Chia-Chi Chang Chun-Yung Chi Chun-Chung Chen Ningfeng Huang Shermin Arab Jing Qiu Michelle L. Povinelli P. Daniel Dapkus Stephen B. Cronin 

机构地区：[1]Department of Physics [2]Center for Energy Nanoscience [3]Department of Electrical Engineering [4]Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089, USA

出　　处：《Nano Research》2014年第2期163-170,共8页纳米研究（英文版）

摘　　要：We have recently demonstrated that GaAs nanosheets can be grown by metal-organic chemical vapor deposition （MOCVD）. Here, we investigate these nanosheets by secondary electron scanning electron microscopy （SE-SEM） and electron beam induced current （EBIC） imaging. An abrupt boundary is observed between an initial growth region and an overgrowth region in the nanosheets. The SE-SEM contrast between these two regions is attributed to the inversion of doping at the boundary. EBIC mapping reveals a p-n junction formed along the boundary between these two regions. Rectifying I-V behavior is observed across the boundary further indicating the formation of a p-n junction. The electron concentration （ND） of the initial growth region is around 1 × 10^18 cm^-3, as determined by both Hall effect measurements and low temperature photoluminescence （PL） spectroscopy. Based on the EBIC data, the minority carrier diffusion length of the nanosheets is 177 nm, which is substantially longer than the corresponding length in unpassivated GaAs nanowires measured previously.

关 键 词：MOCVD GAAS NANOSHEETS EBIC Hall measurement secondary electronemission 

分 类 号：TN213[电子电信—物理电子学] TN305.3