Storm, P.P.StormBar, M.S.M.S.BarSelle, S.S.SelleWenckstern, H. vonH. vonWencksternGrundmann, M.M.GrundmannLorenz, M.M.Lorenz2022-03-062022-03-062021https://publica.fraunhofer.de/handle/publica/26875510.1002/pssr.202100214The impact of the intentional selenium doping of CuI thin films is investigated concerning crucial crystalline, electrical and optical properties. For selenium contents in between 𝑥(Se)= 0.1 at.% and 𝑥(Se)= 1 at.%, the carrier density can be systematically adjusted by the selenium supply during growth between 𝑝=1015 cm −3 and 𝑝=8×1017 cm −3 while transparency and crystallinity remain unaffected. By temperature-dependent Hall-effect measurements, a carrier freeze out is observed and the binding energy of the selenium dopant is determined. The long-term electrical stability in combination with Al2O3 cappings is significantly improved compared to undoped or oxygen doped CuI. However, for selenium contents exceeding 𝑥(Se)= 1 at.%, major crystalline changes are observed that are presumably correlated to a phase transformation. Transmission and electrical measurements suggest that the solubility limit of Se in CuI is about 1 at.% since a degradation of the transparency and decreasing free hole densities are observed for Se contents exceeding 1 at.%. Hence, the doping limit for Se in CuI corresponds to ≈1 at.%.en530journal article