Buried heterostucture lasers using a single-step metal-organic chemical vapor deposition growth over patterned substrates

A single-step metal organic chemical vapor deposition (MOCVD) growth has been used to fabricate a buried heterostructure InGaAs/GaAs multi-quantum well laser over a patterned GaAs substrate. The pattern used here is a re-entrant mesa formed by wet chemical etching oriented along [011] direction. Growth over the mesa results in isolated buried heterostructures. The 250 micrometers long lasers have threshold currents of 30 mA and emit > 100 mW/facet at room temperature. The external differential quantum efficiency is found to be almost independent of temperature in the temperature range of 10 degree(s)C to 90 degree(s)C which suggests a low temperature dependence of leakage current. The threshold current of the laser as a function of temperature can be represented by the usual expression Ith approximately Io exp(T/To) with a characteristic temperature (To) of about 120 K in the temperature range 10 degree(s)C to 90 degree(s)C.