Minority Carrier Lifetimes in InSb/InAsSb Quantum Dot and InAsSb nBn Photodetectors

摘要

The energy level scheme and the minority carrier lifetime in a type-II midwave InSb/InAsSb quantum dot structure were compared with bulk InAsSb using photoluminescence, absorption, and optical modulation response. Two hole energy levels separated by meV were identified in the quantum dots, and a decrease of the hole energy barrier with increasing temperatures was observed. The quantum dot minority carrier lifetime increased from 700 ns at 77 K to 1230 ns at 175 K, and is significantly longer than the bulk InAsSb lifetime of 300 ns. By insertion of quantum dots in the bulk material, the dominating recombination mechanism changed from the Shockley–Read–Hall to radiative recombination.