Dark Current Minimization in Type-II Superlattice Photodetector

Type-II Superlattice (T2SL) photodetectors are at the forefront of optoelectronic detector technology, primarily attributed to their excellent band gap tunability and outstanding optoelectronic characteristics. However, the presence of dark current necessitates the use of an extra cryogenic setup and limits the detector's performance. Therefore, it is essential to understand and minimize the dark current. In this work, we study the dark current characteristics of 10monolayer (ML)/10ML InAs/GaSb T2SL p-i-n photodetector, using TCAD Sentaurus in a reverse bias voltage range at a temperature of 77K. We analyze the variation in the generation-recombination (GR) current, trap assisted tunneling (TAT) current and band to band tunneling (BTBT) current with respect to the thickness of the absorber layer. With an increase in the thickness of the absorber layer, there is a slight increase in the depletion width. Consequently, the GR current increases slightly. As thickness of the absorber layer increases, we observe a decrease in the electric field. Consequently, we achieve a remarkable reduction in the band to band and trap assisted tunneling current.