Composition dependence of the energy gap of ZnxMn1 − xIn2Se4 and optical absorption spectroscopy

Studies on the Zn x Co 1−x S thin films: A facile synthesis process and characteristic properties

“…The lower wavelength range shift in the absorption coefficient with increase in Zn content can be explained with sp-d exchange interaction between the band electrons in CoS and localized d electrons in Zn 2+ [8,9,32,34,35]. In the present system, zinc plays a two-fold role [34,35]: first, it occupies partially vacant Co sites and manipulates the defect states and secondly, it forms a semiconducting alloy whose composition controls the band structure and lattice spacing. The values of the optical band gaps were then calculated from the best straight line fits in the (αhν) 2 versus hν plots (figure not shown) and corresponding band gaps were obtained from the extrapolation of the straight portion of the graph at (αhν) 2 = 0 and cited in table 2.…”

“…A systematic increase in α may be attributed to the creation of more localized states within the band tails of valence and conduction bands due to the existence of defects and disorders [31][32][33]. The lower wavelength range shift in the absorption coefficient with increase in Zn content can be explained with sp-d exchange interaction between the band electrons in CoS and localized d electrons in Zn 2+ [8,9,32,34,35]. In the present system, zinc plays a two-fold role [34,35]: first, it occupies partially vacant Co sites and manipulates the defect states and secondly, it forms a semiconducting alloy whose composition controls the band structure and lattice spacing.…”

The fundamental absorption edge in MnIn2Se4 layer semi-magnetic semiconductor

“…This is because the interpretation of the limited amount of optical data near the band edge reported in the literature is scarce and contradictory. Thus, although no detailed analysis of the spectral dependence of the absorption coefficienthas been performed it has been suggested [24][25][26] that MnIn 2 Se 4 is a direct-lowest-band gap semiconductor with energy gap E G between 1.55 and 1.85 eV at room temperature. However, Neumann et al [23] in studying the absorption coefficient spectra at 295 K for values of lower thancm -1 found an indirect transition at h 1.378 eV followed by a second intra-band transition at h 1.56 eV whose nature (direct or indirect) could not be identified due to the limited range of  data at higher energies.…”

“…In spite of its importance, optical properties of MnIn 2 Se 4 have been studied in less detail [23][24][25][26] and the nature of its fundamental absorption edge is not well established yet. This is because the interpretation of the limited amount of optical data near the band edge reported in the literature is scarce and contradictory.…”

Electrical Conduction Mechanisms and Dielectric Constants of Nanostructure Zinc Indium Selenide Thin Films

“…ZnIn 2 Se 4 has potential applications in photo electronics, photovoltaics (Luengo et al, 1996 andGrilli et al, 1976), buffer layer in the fabrication of heterojunction solar cells (Babu et al, 2011) and also in the development of electro-80 optical memory devices (Hendia and Soliman 1995, Filipowicz et al, 1981and Edwards Soliman et al, 1999. Thin films of Znln 2 Se 4 were prepared by different techniques such as thermal evaporation .…”