Studies of Quantum Dot Infrared Photodetectors

• Main Authors: Chueh Jen Lin, 林決仁
• Other Authors: Chien Ping Lee
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/02331153305739745843

碩士 === 國立交通大學 === 電子工程系 === 91 === The thesis contains two topics about the transport characteristics of QDIPs. First, an investigation on responsivity was practiced. We have demonstrated that there are three major different features in response behavior between QDIPs and QWIPs, including: electric field dependence, temperature dependence, and bending phenomenon. We have proposed a related simple model to explain the electric field dependence of photo-response behavior. A good simulation was achieved with two reasonable fitting parameters. Generally speaking, gain was the dominant factor which affects responsivity strongly. More precise description must be that the gain and quantum efficiency dominate the responsivity alternately under low-field. As electrons draw sufficient energy from the increasing bias, avalanche mechanism will dominate transport behavior. At very high field, the response will bend down due to some scattering. Second, we focused on the activation energy issue. Our results showed that the activation energy of QDIPs was strongly bias-dependent. It decreased almost linearly with bias whether in thin barrier or in thick barrier QDIPs. Activation energy behaved almost the same when we viewed these two samples under electric field scale. The resonant tunneling is a possible reason for this behavior. We propose some performance improving method to QDIPs based on these two fundamental researches. We will firstly try to tune the bound state out of the quantum dots for better quantum efficiency and lower dark current.