Effect of substrate temperature and laser wavelength on pulsed laser deposited CdTe thin films

The effect of substrate temperature and laser wavelength on the laser deposition of CdTe thin films has been studied. CdTe thin films synthesized on glass substrates have been studied using X-ray spectral microanalysis, X-ray diffraction and scanning electron microscopy. It has been shown that the ratio of elements in the CdTe thin films depends on both the substrate temperature and the laser wavelength. Specific features of the crystalline structure, phase composition and structural parameters of the synthesized CdTe films depending on the deposition process conditions (substrate temperature 100–400 °С, laser wavelength 600–1200 nm) have been revealed. Specifically, CdTe thin films deposited using laser radiation of wavelengths of 600 and 1200 nm have a cubic crystalline structure, while CdTe films obtained at a laser wavelength of 1064 nm have either a hexagonal structure or are a mixture of cubic and hexagonal phases, depending on the substrate temperature. At a low substrate temperature (100 °C) the films crystallize to a hexagonal structure, whereas at higher temperatures (200, 300 and 400 °C) the films are a polycrystalline mixture of cubic and hexagonal CdTe phases, growing predominantly along the [111]C direction. It has been shown that CdTe thin films on glass substrates have similar morphologies but different thicknesses, regardless of deposition conditions.