Doping of CuInSe₂ Crystals: Evidence for Influence of Thermal Defects

Annealing of p-CuInSe₂ crystals at low (250–300 °C) and high (600–650 °C) temperatures in the presence of CuInSe₂ powder with a variety of (native) dopants showed the temperature rather than the nature of the dopant to be the major factor in determining the resultant carrier type and concentration. Experiments without added dopant indicate, for samples from a different boule, that type conversion occurs upon annealing between 550 and 650 °C. These results can be explained by thermally induced changes in relative concentrations of intrinsic defects (that were frozen in during crystal cooling) via complex formation and temperature-dependent ionization of defects and their complexes.