Effect of surface treatment on leakage current of GaAs/AlGaAs laser microcavities

Abstract

The effect of surface treatment on leakage current is investigated for two structures of the electropumped GaAs/AlGaAs laser microcavities, one with mesa and the other with hyperboloid-drum structures. Using surface sheet resistivity as a figure-of-merit parameter, the results of different surface treatment methods are compared. The best result is obtained when the sample has been polished in a H2SO4:H2O2:H2O=1:8:1000 solution for 5 s, and treated subsequently in a 6% excess sulfur-containing (NH4)(2)S-x solution at 60 degreesC for 8 mins. The treatment in (NH4)(2)S-x solution increases the surface sheet resistivity by a factor of similar to14. The cross-sectional shape of the cavity and the vertical profile of distributed Bragg reflector mirrors have little correlation with the leakage current. (C) 2003 American Institute of Physics.