New material systems for third generation infrared photodetectors

Third-generation infrared (IR) systems are being developed nowadays. In the common understanding, these systems provide enhanced capabilities-like larger numbers of pixels, higher frame rates, and better thermal resolution as well as multicolour functionality and other on-chip functions. In this class of detectors, two main competitors, HgCdTe photodiodes and quantum-well photoconductors, have being developed. Recently, two new material systems have been emerged as the candidates for third generation IR detectors, type II InAs/GaInSb strain layer superlattices (SLSs) and quantum dot IR photodetectors (QDIPs). In the paper, issue associated with the development and exploitation of multispectral photodetectors from these new materials is discussed. Discussions is focused on most recently on-going detector technology efforts in fabrication both photodetectors and focal plane arrays (FPAs). The challenges facing multicolour devices concerning complicated device structures, multilayer material growth, and device fabrication are described.