Structure of CdZnTe films on glass

Abstract

Polycrystalline Cd1−xZnxTe films were grown on glass substrates over the full range of compositions (0 < x < 1) by metal–organic chemical vapour deposition at 480 °C. The films (∼5 µm thick) showed uniform texture oriented along the ⟨1 1 1⟩ direction, perpendicular to the substrate, independent of the film composition. The dependence of the lattice parameter of cubic Cd1−xZnxTe on the composition followed Vegard's law. The thick Cd1−xZnxTe films were shown to be of a single phase and structurally stable. The average grain size in the thick films was in the range 3–5 µm. The dominant imperfections in the films were twins (mostly Σ = 3) and dislocations. The x-ray diffraction (XRD) FWHM parameter reached a maximum at x = 0.5. Transmission electron microscopy (TEM) in situ heating in the range 200–400 °C caused plastic deformation in the grains without causing ordering effects. Optical absorption and low-temperature photoluminescence measurements confirmed the XRD and TEM results.

Photoluminescence of CdZnTe thick films obtained by close-spaced vacuum sublimation

“…At present different methods of Cd 1 À x Zn x Te films deposition such as metalorganic vapor-phase epitaxy [9] metal-organic chemical vapor deposition [10], pulsed laser deposition [11], thermal Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/jlumin evaporation [12,13], brush plating technique [14], magnetron sputtering [15], hot wall epitaxy [16], laser ablation [11] were used. Earlier [17], it was shown that a low cost close-spaced vacuum sublimation (CSVS) method makes it possible to deposit the stoichiometric films of II-VI semiconductors with the controllable physical properties using a glass as substrate.…”

“…Earlier, different properties of thin and thick films have been studied in Refs. [10,[26][27][28]. It was shown [26] that Cd 1 À x Zn x Te (xr 0.54) layers with typical thicknesses of 2-3 μm deposited by molecular beam epitaxy on GaAs substrates observe narrow (PL) bands at higher energies which are attributed to bound exciton (BE) recombinations and the broader bands e-A, which arising from band-to-acceptor radiative transitions.…”

“…[27] using the thermal evaporation method on carbon substrate, where the high signal-to-noise ratios of the X-ray detector have been obtained. A wide range of compositions of Cd 1 À x Zn x Te thick films on glass substrates were produced by metal-organic chemical vapor deposition [10], where it was shown that these films were composed of a single phase and were structurally stable. It was shown [10] that PL spectra in the range of the Cd 1 À x Zn x Te band gap present intense peaks, corresponding to BE and relatively wide bands due to defect-impurity recombination.…”

“…A wide range of compositions of Cd 1 À x Zn x Te thick films on glass substrates were produced by metal-organic chemical vapor deposition [10], where it was shown that these films were composed of a single phase and were structurally stable. It was shown [10] that PL spectra in the range of the Cd 1 À x Zn x Te band gap present intense peaks, corresponding to BE and relatively wide bands due to defect-impurity recombination. However, identification of defect structure has not been attempted in these papers [10,26].…”

“…It was shown [10] that PL spectra in the range of the Cd 1 À x Zn x Te band gap present intense peaks, corresponding to BE and relatively wide bands due to defect-impurity recombination. However, identification of defect structure has not been attempted in these papers [10,26]. The crystalline quality of large grain size Cd 1 À x Zn x Te with high Zn concentrations (0.45 ox o0.85) grown by a zone melting process was investigated using their complex study [28].…”