Visible cathodoluminescence from nanocrystalline GaSb obtained by mechanical milling

Abstract

The luminescence of mechanically milled GaSb has been investigated by means of cathodoluminescence (CL) in the scanning electron microscope. Transmission electron microscopy reveals that the GaSb powders obtained after the milling process contain nanocrystals with sizes of few nanometers. CL spectra of the GaSb powders show a bright blue-green luminescence visible to the naked eye, even at room temperature. Furthermore, a shift from blue to green has been observed depending on the milling time. In order to clarify the origin of this visible luminescence, we have performed a CL study on gallium oxide (Ga2O3) and antimony oxide (Sb2O3) powders, which exhibit several emission bands in the visible range. Comparison of these results with CL spectra from GaSb powders shows that oxidation during the milling process of GaSb plays an important role in the luminescence features observed.