On the bowing parameter in Cd1−xZnxTe

Abstract

Cd 1−x Zn x Te thin films were prepared on 7059 Corning glass substrates using an rf magnetron sputtering system and CdTe(1−y)+ZnTe(y) targets. The concentration (x) of Zn in the films did not coincide with the relative weight (y) of the ZnTe powder in the compressed targets. Values of x were in the range 0–0.30 as determined from x-ray diffraction patterns. The band gap energy (Eg) of the Cd1−xZnxTe samples was calculated from the photoreflectance spectra measured on the films. The position of the experimental points in the Eg versus x plot show a deviation from the phenomenological quadratic relation Eg=Eg0+ax+bx2 calculated within the virtual crystal approximation (VCA). The depart of the Eg values for higher Zn concentrations from the expected VCA model is probably due to a larger clustering of Zn atoms and/or a percolation phenomena. We obtain fitted values for the parameters a and b within the VCA approach. Comparison with data reported by other authors is made.

Studies on morphological change and optical properties for various Zn concentrations in CdTe thin film prepared by stacked elemental layer method

“…Zn = 0.20% and 0.25%). It is contrary for the reported results [24]. However, the peak sharpness is found to decrease with increasing zinc content.…”

Absence of the bowing character in the common-anion II–VI ternary alloys

“…For both of these data sets, the bandgap energy is seen to increase almost linearly with composition over the entire range of 0 ≤ x ≤ 1 and , therefore, the bowing parameters are found to be very small. At room temperature (RT), Zelaya-Angel et al [34] reported their photo-reflectance measurements on CdZnTe thin films grown by the sputtering technique. Although raising the the temperature usually causes a reduction in the bandgap energy, the bowing, as reported by these authors [34], remains limited and small (b = 0.10 ± 0.01 eV).…”

“…At room temperature (RT), Zelaya-Angel et al [34] reported their photo-reflectance measurements on CdZnTe thin films grown by the sputtering technique. Although raising the the temperature usually causes a reduction in the bandgap energy, the bowing, as reported by these authors [34], remains limited and small (b = 0.10 ± 0.01 eV). Our calculated bandgap energies for the same alloys are shown in Fig.…”

Free‐exciton absorption in bulk CdTe: temperature dependence

“…The value of E g at liquid-helium temperature is well established as 1.606 eV. But discrepancies for the reported value of E g at room temperature (RT) are large, ranging from 1.49 to 1.53 eV, as summarized by Lee et al [1] and Zelaya-Angel et al [2]. It seems that the actual generally accepted value of E g is 1.512 ± 0.003 eV, as deduced from photoreflectance and electroreflectance methods [1,3].…”