Carrier transport in III–V quantum-dot structures for solar cells or photodetectors

• Published in: Chinese physics B Vol. 25; no. 9; pp. 174 - 179
• Main Author: 王文奇 王禄 江洋 马紫光 孙令 刘洁 孙庆灵 赵斌 王文新 刘伍明 贾海强 陈弘
• Format: Journal Article
• Language: English
• Published: 01.09.2016
• Subjects: 光电探测器; 光电转换原理; 共振激发; 半导体物理学; 太阳能电池; 热电子发射; 载流子输运; 量子点结构
• ISSN: 1674-1056; 2058-3834
• DOI: 10.1088/1674-1056/25/9/097307

According to the well-established light-to-electricity conversion theory,resonant excited carriers in the quantum dots will relax to the ground states and cannot escape from the quantum dots to form photocurrent,which have been observed in quantum dots without a p–n junction at an external bias.Here,we experimentally observed more than 88% of the resonantly excited photo carriers escaping from In As quantum dots embedded in a short-circuited p–n junction to form photocurrent.The phenomenon cannot be explained by thermionic emission,tunneling process,and intermediate-band theories.A new mechanism is suggested that the photo carriers escape directly from the quantum dots to form photocurrent rather than relax to the ground state of quantum dots induced by a p–n junction.The finding is important for understanding the low-dimensional semiconductor physics and applications in solar cells and photodiode detectors.