Abstract
Non-destructive, reliable, and accurate measurements of low doping levels carrier lifetimes in small direct-bandgap semiconductors such as indium arsenide (InAs) at room temperature are challenging due to intrinsic limitations conventional experimental techniques. In this article, we introduce a contactless optical-terahertz (THz) pump–probe technique continuous-wave regime measuring the 1015−1016cm−3 range down 8 ns InAs. We show that single-parameter material model can be used retrieve free density from THz transmission InAs layers. Additionally, lifetime photogenerated excess carriers measured by modulating using an amplitude-modulated optical pump.