Surface recombination in dry etched AlGaAs/GaAs double heterostructure p-i-n mesa diodes

We have measured the surface recombination in reactive ion etched mesas in an AlGaAs/GaAs p-i-n double heterostructure using the size dependence of the current density versus voltage characteristic. The recombination current is dependent on processing due to surface oxide formation. The surface recombination of the oxidized surface is independent of the crystal axis. The recombination current can be reduced by removal of the oxide and sulfur passivation which protects the surface from further oxidation.