Deep hole traps inp-type GaSe single crystals

Abstract

Space-charge-limited-current measurements have been performed at room temperature on GaSe single crystals. The samples investigated were $p$ type and were grown from the melt by using the Bridgman-Stockbarger method. Three well-defined deep-lying hole traps have been found at 0.421, 0.465, and 0.543 eV above the valence band, respectively, and with concentrations ranging between ${10}^{12}$ and ${10}^{13}$ ${\mathrm{cm}}^{-3\mathrm{}}$. Their capture cross section has been found to be of the order of ${10}^{-12\mathrm{}}$ ${\mathrm{cm}}^2$, i.e., large enough to classify these traps as "giant traps." The origin and the nature of these centers is discussed and their possible connections with crystallographic, electrical, and optical properties of GaSe are extensively investigated.