MINIMIZATION OF THRESHOLD CURRENT IN SHORT-WAVELENGTH ALGAINP VERTICAL-CAVITY SURFACE-EMITTING LASERS

This paper investigates the interdependence of wavelength and threshol d current in an AlGaInP vertical-cavity surface-emitting laser with an emphasis on optimizing the performance of shorter wavelength lasers. We apply a model which includes bandstructure, band-filling and many b ody effects in a consistent manner, as well as leakage current effects , to evaluate the effect of strain and quantum confinement on threshol d current. We find that leakage current becomes increasingly important for shorter wavelength devices, comprising more than half of the tota l current for a laser emitting at 620 nm. The reduction of threshold c urrent with increasing compressive strain is clearly demonstrated and the dependence of threshold current density on quantum well width is f ound to be greater for shorter wavelength lasers.