Effect of carrier diffusion in oxidized vertical-cavity surface-emitting lasers determined from lateral spontaneous emission

Abstract

The effect of carrier diffusion on threshold current is studied quantitatively for the oxide-aperturbed 780 nm vertical-cavity surface-emitting lasers (VCSEL) from the measured spontaneous emission, The oxide aperture size of 2-10 mu m is prepared and characterized, The diffusion coefficient of 4.6 cm(2)/s and the nonradiative recombination coefficient of 6.8x10(7)/s are obtained using the independence of the nonradiative recombination coefficient on the laser aperture size, The contribution of carrier diffusion loss is 42% of the threshold current for the 2 mu m VCSEL, The relative contribution of the diffusion becomes smaller for the larger devices as is expected. (C) 1997 American Institute of Physics.