GALLIUM NITRIDE WHISKERS FORMED BY SELECTIVE PHOTOENHANCED WET ETCHING OF DISLOCATIONS

Gallium nitride is used to fabricate high brightness blue and green li ght-emitting diodes in spite oi high densities of extended structural defects. We describe a photoelectrochemical etching process that revea ls the dislocation microstructure-of it-type GaN films by selectively removing material between dislocations. The GaN whiskers formed by the etching have diameters between 10 and 50 nm and lengths of up to 1 mu m. A correlation between the etched features and threading dislocatio ns in the unetched film is confirmed through transmission electron mic roscopy studies. The whisker formation is believed to be indicative of electrical activity at dislocations in GaN. (C) :1998 American? Insti tute of Physics. [S0003-6951 (98)02932-5].