Designing guidelines for possible continuous-wave-operating nitride vertical-cavity surface-emitting lasers

Abstract

A detailed self-consistent threshold simulation of the continuous wave (CW) operations at room temperature (RT) of possible GaN/AlGaN/AlN vertical-cavity surface-emitting lasers (VCSELs) is developed in a simple mathematical form in order to give an opportunity for it to be carried out using only PC-level computing power. In the analysis, the mismatch-related phenomena and temperature dependences of many model parameters are included with the aid of a self-consistent approach. Multiple-quantum-well (MQW) structures are proved to be the best suited for RT CW nitride VCSEL devices. In contrast, currently available nitride technology practically excludes the possibility of an efficient RT CW operation of single-quantum-well (SQW) nitride VCSELs. Double-heterostructure (DH) nitride VCSELs are found to be less sensitive to increases in optical losses than other nitride VCSELs, therefore their RT CW operation, if possible, may occur for a wider current range than that in QW VCSELs. It is also revealed that substrate material has a critical influence on the possibility of reaching RT CW thresholds, which strongly favours the SiC substrate of very high thermal conductivity.