Minimization of threshold current in short wavelength AlGaInP vertical-cavity surface-emitting lasers

This paper investigates the interdependence of wavelength and threshold 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 body effects in a consistent manner, as well as leakage current effects, to evaluate the effect of strain and quantum confinement on threshold current. We find that leakage current becomes increasingly important for shorter wavelength devices, comprising more than half of the total current for a laser emitting at 620 nm. The reduction of threshold current with increasing compressive strain is clearly demonstrated and the dependence of threshold current density on quantum well width is found to be greater for shorter wavelength lasers