Spectral tuning and linewidth narrowing of shallow junction surface emitting GaAs LED's through gamma -ray irradiation

Alterations of device characteristics as a result of gamma -ray irradiation of shallow-junction surface emitting devices are different from those of deep-junction devices with respect to LED emission intensity reduction, I-V curve, line shape, and spectral shift. In particular, much larger spectral shifts in the opposite direction-toward longer wave-lengths-are reported here than those found in the literature for deep-junction devices. A qualitative model based upon photochemical doping and changes in surface band bending is proposed to explain these phenomena.