Optoelectronic properties of Cd1−xZnxTe films grown by molecular beam epitaxy on GaAs substrates

Abstract

Photoluminescence (PL) experiments were carried out at 300 and 12 K to investigate the electro-optical properties of Cd1−xZnxTe grown by molecular beam epitaxy on GaAs substrates. The compositional dependence of the band-gap energy was determined. It has a quadratic dependence on x. The near band edge PL spectra at 12 K show free and bound exciton lines for x=0 and 1 and only broadened bound exciton peaks for other compositions. The bound exciton broadenings are quantitatively explained based on the compositional fluctuations of the cations. The PL line shapes give indications of the high quality of the layers.

Composition dependence of structural and optical properties of Cd1−Zn Te thick films obtained by the close-spaced sublimation

“…In particular, 1LO 1 , 2LO 1 and 3LO 1 replicas were detected (Fig.5c). Thus, the RS study of pure CdTe sample suggests application of IR (E=1.579 eV) excitation for the resonant enhancement of the RS signal of CZT1 sample with comparatively low zinc concentration (x=0.10) since the value of BG at room temperature for this sample is about 1.57 eV [39]. At the same time, the 633 nm excitation (E=1.958 eV) is more suitable for wider band gap CZT2, CZT3, CZT4 and ZnTe samples.…”

Chemical etching and surface oxidation studies of cadmium zinc telluride radiation detectors

“…The Zn concentration for both materials was approximately 5 at.% (determined by photoluminescence (10) respectively, using the equation (11);…”

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

“…[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. The BE broadenings are attributed to statistical fluctuations in the concentrations of the cation atoms.…”

“…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].…”