뜨거운 곁쌓기 법에 의해 성장된 MgGa2Se4 단결정 박막의 열처리 효과

Abstract

The evaporating materials for MgGa2Se4 single crystal thin films was prepared from horizontal electric furnace. To obtain the single crystal thin films, MgGa2Se4 compounded polycrystal powder was deposited on thoroughly etched semi-insulated GaAs(100) substrate by the hot wall epitaxy (HWE) method system. The source and substrate temperatures of optimized growth conditions, were 610oC and 400oC, respectively.The source and substrate temperatures were 610oC and 400oC, respectively. The crystalline structure of the single crystal thin films was investigated by double crystal X-ray diffraction (DCXD). The temperature dependence of the energy band gap of the MgGa2Se4 obtained from the absorption spectra was well described by the Varshni's relation, Eg(T) = 2.34 eV-(8.81X10-4 eV/ K)T2/(T+251 K). After the as-grown MgGa2Se4 single crystal thin films was annealed in Mg-, Se-, and Ga-atmospheres, the origin of point defects of MgGa2Se4 single crystal thin films has been investigated by the photoluminescence (PL) at 10 K. The native defects of VMg, VSe obtained by PL measurements were classified as a donors or acceptors type. And we concluded that the heat-treatment in the Se-atmosphere converted MgGa2Se4 single crystal thin films to an optical n-type. Also, we confirmed that Ga in MgGa2Se4/GaAs did not form the native defects because Ga in MgGa2Se4 single crystal thin films existed in the form of stable bonds.