Photoluminescence of porous gallium arsenide

Photoluminescence in the visible and infrared regions of the spectrum is investigated for porous gallium arsenide prepared by the electrolytic or chemical etching of GaAs. The IR luminescence band of porous GaAs is shifted from the maximum for crystalline GaAs into the long-wavelength region of the spectrum and has a greater width. All the samples are characterized by a broad emission band in the visible region; the intensity and shape of the band depend on the layer preparation conditions. Two maxima are discernible in the band in the vicinity of 420 nm and 560 nm. An explanation is given for both the visible luminescence and the modification of the IR band of porous GaAs. It is concluded from a comparison of the visible luminescence of porous GaAs with emission from hydrated oxides of arsenic and gallium that the visible-range luminescence of porous GaAs, especially when prepared by chemical etching, is determined in large measure by the presence of oxides. Considerations are set forth as to ways of creating quantum-size formations on the surface of GaAs. (C) 1997 American Institute of Physics. [S1063-7826(97)02511-8].