Kelvin probe force microscopy of hole leakage from the active region of a working injection-type semiconductor laser diode

Abstract

A method that enables direct observation and quantitative characterization of carrier leakage from the active region of working semiconductor light-emitting diodes and lasers is developed on the basis of Kelvinprobe microscopy. The method is used to reveal, on the surface of the mirror surfaces of high-power InGaAs/AlGaAs/GaAs laser diodes, minority holes arriving from the active region and spreading to the surface regions over the n-type emitter and n-type substrate. It is shown that holes can move through surface channels formed by regions of surface band bending to distances of tens of micrometers from the place where they originally appear at the surface. It is demonstrated that, as the injection current increases, the amount of leakage gradually grows and stabilizes after the onset of lasing.