GERMANIUM SELF-ASSEMBLED QUANTUM DOTS IN SILICON FOR MID-INFRARED PHOTODETECTORS

We present an overview of the experimental results in the field of quantum dot infrared photodetectors (QDIPs) implemented on Ge self-assembled quantum dots (QDs) in Si. QDs are fabricated using Stranski-Krastanov epitaxial growth mode. The effect of photoconductivity is associated with the photoexciation of holes from bound to bound states in Ge QDs or from bound states in Ge dots to continuum states in the Ge wetting and Si barrier layers. The depolarization field effect in the collective interlevel excitations of a dense array of Ge/Si QDs is discussed. The comparison between operating characteristics of QDIPs based on III-V and Ge/Si heterostructures is included.