Molecular beam epitaxial growth effects on type-II antimonide lasers and photodiodes

Abstract

Two important classes of electro-optical devices, midwave-infrared interband cascade lasers (ICLs) and long-wave infrared photodiodes, employ type-II antimonide active regions grown by molecular beam epitaxy (MBE). The authors have studied how growth temperature and As flux affect the integrated intensity and linewidth of low-temperature photoluminescence spectra emitted from ICL active regions. Possible ramifications for defect-assisted Auger processes are discussed, and experimental Auger coefficients are extracted from the measured ICL thresholds and slope efficiencies. They also demonstrate that the effective dynamic impedance of a type-II photodiode with graded-gap depletion region is quite sensitive to the doping level in the absorber. Majority acceptor concentration is a key design parameter that must be carefully controlled in the MBE growth.