“…1) There are several applications of SiGe in optical devices, like photodetector, terahertz laser, 2) high electron mobility transistor (HEMT), and heterojunction bipolar transistor (HBT). 3) Most recently, the quantum dot infrared photodetector (QDIP) has attracted a lot of attentions because it possesses merits of high quantum efficiency, 4) normal incident, low dark current as compared to the quantum well infrared photodetector (QWIP). 5,6) Many experimental techniques, such as Raman, 7) Fourier transform infrared spectroscopy (FTIR), and photoluminescence (PL), 8) had been used to characterize the optical and electronic properties of the Ge quantum dot/Si superlattice.…”