OPTIMAL CRYSTAL-GROWTH CONDITIONS OF THIN-FILMS OF BI2TE3 SEMICONDUCTORS

Crystal growth conditions of Bi2Te3 narrow bandgap semiconductors have been studied using molecular beam epitaxy method. It was applied to the growth of Bi2Te3 on Bridgman single-crystal substrate Sb2Te3. Substrate ingots were taken from the natural cleavage along the (0001) plane. The deposited conditions have been studied as a function of substrate temperature (T(S)) and flux ratio (F(R) = F(Te)/F(Bi)). The quality of deposited layers was controlled by X-ray diffraction, scanning electron microscope (SEM), secondary ion mass spectroscopy (SIMS) depth profiling and energy-dispersive X-ray (EDX) microanalyser. The sticking coefficients K(S)(Te) and K(S)(Bi) of the elements that compose Bi2Te3 were determined. It was found that the stoichiometry of deposited layers depended on substrate temperature and flux ratio. It was observed that all deposited layers were single-crystal in the orientation of their substrates with a small shift due to the stress in layer.