Avalanche injection laser in p-type GaAs

Light emission between liquid helium temperature and room temperature, as well as lasing below 90°K, has been observed from p-type GaAs structures containing high resistivity regions. These regions are obtained at the boundary of the zinc layer when zinc is diffused into (p-type) manganese-doped GaAs. Voltage probes along the current direction, normal to the interface between the zinc and manganese dominated regions, show that the high resistivity region is p-type. The temperature dependence of the resistance of the region shows that it is still dominated by manganese, as is the bulk material into which the zinc is diffused. No unequivocal determination of the width of the region could be made, but various indications show that it is of the order of one micron. In lasing structures zinc is diffused into the opposite faces of a manganese doped wafer in such a fashion that the central region and the two zinc diffused regions are each approximately 0.001" wide. When the voltage applied to a unit is of the order of twenty volts, a sharp increase in current occurs accompanied by light emission. The critical voltage is not strongly temperature dependent, varying only a few volts between room temperature and liquid helium temperature. It is believed that the light emission is the result of an avalanche breakdown of the high resistivity regions.