Modification of exciton binding energy in the horizontal Bridgman-Stockbarger growth of InSe by Ho doping

摘要

Undoped InSe and Ho doped InSe single crystals with various Ho concentrations were grown by the horizontal Bridgman-Stockbarger method. The absorption measurements were carried out in the temperature range 10-320 K. Exciton binding energies, steepness parameters, and Urbach energies of InSe and InSe:Ho samples were investigated as a function of temperature. Ho doping caused a shift towards longer wavelengths in the absorption edge. In general, Ho doping causes certain increases in the exciton binding energy and Urbach energy, and a decrease in the steepness parameter. An enhancement of exciton binding energy up to about 55 meV is observed at 0.0025 mass ratio of Ho. (C) 2004 American Institute of Physics.