Reactive-ion-etched gallium nitride: Metastable defects and yellow luminescence

Gallium nitride has been reactive-ion etched with SF6 and argon plasmas. Th e Ar-etched samples show a striking transition from a dominant blue lumines cence band to a dominant yellow luminescence band after less than 5 min of low power illumination. The observation of metastable defects which are ass ociated with both the yellow and blue bands has important consequences for our understanding of defect-related luminescence in gallium nitride. (C) 19 99 American Institute of Physics. [S0003-6951(99)00747-0].