Dependence of film texture on substrate and growth conditions for CdTe films deposited by close-spaced sublimation

The texture of CdTe films deposited via close-spaced sublimation (CSS) was studied. Different substrates were used, including Si(100), fluorine-doped SnO₂ (FTO), and CdS, and different growth conditions were applied. The texture behaviors of each sample were evaluated based on its XRD spectrum and are found to be dependent on both the substrate and the growth conditions. The texture strength is found to be, in order, Si(100) > FTO > CdS at a substrate temperature of 763 K under 100 Pa Ar, which is the opposite of the order of the surface roughness of the substrates. The textures of the films on FTO and chemical bath deposition (CBD)-CdS substrates, especially on CBD-CdS, are very sensitive to the growth conditions, whereas those on Si(100) are not. It is found that the texture is strengthened at elevated temperatures and suppressed under decreased ambient pressure. It is also found that the textured films are composed of both (111) and (511) texture components, which is believed to be the result of the twinning in (111) oriented grains.