Effects of ion etching on the optical properties and lattice disorder of GaAs were studied by means of photoluminescence, He backscattering, and enhanced chemical etching. The photoluminescence intensity excited by a He–Cd laser (3250 Å), which penetrates a distance of approximately 150 Å into GaAs, is decreased to less than 20% of the initial value after ion etching by 100-eV Ar and recovered almost completely by 450° C annealing. Helium backscattering and electron diffraction pattern indicate the existence of an amorphous layer, the thickness of which is 20% larger than the value estimated by LSS theory. Photoluminescence measurement shows that beyond this amorphous region there are distributed a lot of nonradiative recombination centers as well as radiative recombination centers which diffuse into the bulk. The depth of this distribution is larger than that of the amorphous region by 1 order of magnitude.
© 1978 Optical Society of AmericaFull Article | PDF Article
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