Improvement of electroluminescence from CdF₂/CaF₂ intersubband transition light-emitting structure by trench patterning and hydrogen annealing of Si substrate

Abstract

An improvement of the electroluminescence (EL) intensity of the CdF₂/CaF₂ intersubband transition (ISBT) light-emitting structure is reported. In the ISBT active region, the precise control of crystal growth is strongly required. In this work, the hydrogen-annealing surface flattening of Si substrates was employed to obtain a high quality active region to suppress non-radiative leakage current. A markedly flat surface was obtained in the 30-µm-wide trench bottom after hydrogen annealing. In the EL measurement of the device fabricated in the trench, the EL intensity was approximately 40 times stronger than that of the device without patterning and hydrogen annealing.