The effect of indium tin oxide as an ohmic contact for the 850 nm GaAs oxide-confined VCSELs

Abstract

In this article, we report the effect of indium tin oxide (ITO) as a p-type ohmic contact for the 850 nm GaAs oxide-confined vertical-cavity surface-emitting lasers (VCSELs). The VCSELs with ITO contact have a threshold current of 0.96 mA, a full-width-at-half-maximum angle of beam divergence of 27° and an ellipticity of 103.8% for the far-field pattern at a 10-mA driving current, which are the same as those of the conventional VCSELs with Au/Zn/Au or Ti/Pt/Au ohmic contacts. In addition, the VCSELs with ITO contact exhibit a light output power of 1.27 times in magnitude higher than those of the conventional VCSELs.