Thermal aspects of designing CW-operated nitride VCSELs

A room-temperature (RT) continuous-wave (CW) operation of possible nitride vertical-cavity surface-emitting lasers (VCSELs) is considered in the prese nt paper using a simple VCSEL simulation to give some essential guidelines for their proper designing. It is revealed that a substrate material has a critical influence on a possibility of reaching RT CW thresholds which prac tically excludes currently used sapphire substrates of relatively low therm al conductivity from this application. SQW nitride VCSELs are found to be v ery sensitive to an increase in temperature, which is followed by their ina ppropriate CW-operation characteristics. A moderate increase in a number of quantum wells in VCSEL active regions significantly improves their CW achi evements, i.e. decreases RT CW thresholds as well as considerably widens th eir CW threshold ranges.