Mixed semiconductor ternary crystals were grown using the Bridgman–Stockbarger method. This is a high–temperature and high–pressure crystal growth method. Cd1–xBexTe crystals were grown in the range of composition 0 < x < 0.1, such as 0.00, 0.01, 0.03, 0.05, and 0.1. The main goal of this paper was to compare the thermal properties of CdBeTe with previously grown CdMnTe and CdZnTe–mixed ternary crystals. The photopyroelectric technique was applied to examine the thermal properties. The thermal diffusivity and effusivity values were obtained after testing all the samples, and the thermal conductivity was calculated then. As such, a complete thermal characterization of the crystals was carried out. For further characterization, the thermal conductivity versus composition was checked by applying the Sadao Adachi model. Thanks to that, we were able to determine the total thermal resistivity of the crystals and the additional resistivity which arises from the lattice disorder. As such, the disorder effects arising from substituting the native atom with a foreign one were characterized for all crystals. We were looking for the best substitution of the Cd atom in the CdTe matrix based on the compounds’ thermal properties. It turned out that Zn and Mn introduce a similar disorder, with Be being the highest one.
Investigated in this work, Cd1−xZnxSe-mixed ternary compounds were grown by the Bridgman method. Several compounds with zinc content varying in the range 0 < x < 1 were produced between two binary parents, CdSe and ZnSe crystals. Using the SEM/EDS technique, the accurate composition of formed crystals was determined along the growth axis. Thanks to that, the grown crystals’ axial and radial uniformity were determined. Characterization of the optical and thermal properties was undertaken. The energy gap was measured using photoluminescence spectroscopy for different compositions and temperatures. The bowing parameter describing the behavior of the fundamental gap with composition for this compound was found to be 0.416 ± 0.06. The thermal characteristics of grown Cd1−xZnxSe alloys were systematically studied. The thermal diffusivity and effusivity of the crystals under investigation were experimentally determined, allowing the calculation of the thermal conductivity. We applied the semi-empirical model that Sadao Adachi developed to analyze the results. Thanks to that, it was possible to estimate the contribution arising from chemical disorder to the crystal’s total resistivity.
Cd1−xBexTe, a new material with potential for X-ray and γ-ray detectors, was analyzed by photothermal piezoelectric spectroscopy. The samples were tested depending on beryllium content and surface preparation. The main aim of the measurements was to extract the energy gap values, which were found for x = 0.01, 0.03, 0.05, and 0.1. It was shown that mechanical (polishing) and chemical (etching) treatment strongly influenced the amplitude and phase spectra of CdBeTe crystals. Piezoelectric spectroscopy allowed for comparing the quality of preparation of both surfaces for a single sample. The sub-surface damaged layer that was created as a result of surface processing had different thermal parameters than the bulk part of the sample. It was responsible for the additional peaks in the amplitude spectrum and changes in the phase spectrum of the photothermal signal. Two different methods of sample etching were analyzed. One completely quenched the signal, and the other did not eliminate the defects present on the surface after the cutting process. The article presents the preliminary interpretation of experimental data using the modified Blonskij model.
Phonon-polaritons (PPs) are phonon–photon coupled modes. Using near-forward Raman scattering, the PP of the cubic Zn1−xMgxTe (x≤ 0.09) semiconductor alloy could be measured. While the PP-coupling hardly develops in pure ZnTe, minor Mg-alloying suffices to stabilize a long-lifetime PP strongly bound to the lattice, i.e., with a pronounced phonon character, and yet a fast one originating from the highly dispersive photon-like bottleneck of the PP-dispersion. By combining the advantages of a phonon and a photon, the long-lifetime PP generated by minor Mg-alloying of ZnTe marks an improvement over the PP of pristine ZnTe, which, from the Raman cross section calculation, can only achieve a balanced compromise between the two kinds of advantages, intensity and speed. The discussion of the PP-related lattice dynamics of Zn1−xMgxTe (x≤ 0.09) is grounded in a preliminary study of the lattice macro- and microstructure using x-ray diffraction and solid-state nuclear magnetic resonance, respectively, and further relies on ab initio calculations of the native phonon modes behind the PP in the Mg-dilute limit of Zn1−xMgxTe (x∼ 0), considering various Mg isotopes.
In the purpose of enhancing solar cell efficiency and sustainability, zinc selenide (ZnSe) and silicon (Si) play indispensable roles, offering a compelling combination of stability and transparency while also highlighting their abundant availability. This study utilizes the SCAPS_1D tool to explore diverse heterojunction setups, aiming to solve the nuanced correlation between key parameters and photovoltaic performance, therefore contributing significantly to the advancement of sustainable energy solutions. Exploring the performance analysis of heterojunction solar cell configurations employing ZnSe and Si elements, various configurations including SnO2/ZnSe/p_Si/p+_Si, SnO2/CdS/p_Si/p+_Si, TiO2/ZnSe/p_Si/p+_Si, and TiO2/CdS/p_Si/p+_Si are investigated, delving into parameters such as back surface field thickness (BSF), doping concentration, operating temperature, absorber layer properties, electron transport layer properties, interface defects, series and shunt resistance. Among these configurations, the SnO2/ZnSe/p_Si/p+_Si configuration with a doping concentration of 1019 cm−3 and a BSF thickness of 2 μm, illustrates a remarkable conversion efficiency of 22.82%, a short circuit current density (Jsc) of 40.33 mA/cm2, an open circuit voltage (Voc) of 0.73 V, and a fill factor (FF) of 77.05%. Its environmentally friendly attributes position it as a promising contender for advanced photovoltaic applications. This work emphasizes the critical role of parameter optimization in propelling solar cell technologies toward heightened efficiency and sustainability.