Growth of thick films CdTe from the vapor phase
Wachstum dicker CdTe-Schichten aus der Gasphase
CdTe films with a thickness of 100 µm were grown by molecular beam epitaxy (MBE) on semi-insulating LEC GaAs (0 0 1) substrates. The films were characterized by X-ray diffraction (XRD), photoluminescence (PL), X-ray photoelectron spectroscopy (XPS), I/V characteristics and detector measurements using a 241Am source. The grown layers were highly oriented as revealed from X-ray pole figure measurements and high-resolution XRD experiments. Low temperature PL measurements showed the formation of A-center complexes including Ga and In acting as donors. Furthermore, the distribution of these impurities in the films was determined by spatially resolved PL measurements. XPS demonstrates the formation of a TeO2 overlayer due to Cd depletion at the surface of the films. The electrical measurements including I/V characteristics and detector measurements resulted in resistivity values of around 3×10(exp 8) ohm cm and a µt product of electrons of 10(exp -5) cm2/V.