The overlooked real cause for high voltage in vertical-cavity surface-emitting lasers

Summary form only given. In this work, we have designed an experiment to show that with proper p/sup +/GaAs-Au contact annealing, device threshold voltage (Vth) is reduced greatly to 1.46 V with merely a simple, uniformly doped InGaAs QW vertical cavity surface emitting (VCSEL) laser structure. Thus, contrary to previous publications, doping and bandgap engineering at heterointerfaces appear not to be very significant. Our results also show that contrary to general belief, Ti-Au or Au on p/sup +/GaAs cap layer can be annealed to obtain better contacts.