| 초록 |
A stoichiometric mixture of evaporating materials for CuInSe2 single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, CuInSe2 mixed crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the hot wall epitaxy (HWE) system. The source and substrate temperatures were 620℃ and 410℃, respectively. The temperature dependence of the energy band gap of the CuInSe2 obtained from the absorption spectra was well described by the Varshni's relation, Eg(T) = 1.1851 eV - (8.99 × 10-4 eV/K)T2/(T + 153K). After the as-grown CuInSe2 single crystal thin films was annealed in Cu-, Se-, and In-atmospheres, the origin of point defects of CuInSe2 single crystal thin films has been investigated by the photoluminescence(PL) at 10 K. The native defects of VCu, VSe, Cuint, and Seint obtained by PL measurements were classified as a donors or acceptors type. And we concluded that the heat-treatment in the Cu-atmosphere converted CuInSe2 single crystal thin films to an optical n-type. Also, we confirmed that In in CuInSe2/GaAs did not form the native defects because In in CuInSe2 single crystal thin films existed in the form of stable bonds. |
