Evolution of the band gap and the dominant radiative recombination center versus the composition for ZnSe1−xTex alloys grown by molecular beam epitaxy

Abstract

We report a systematic study of the optoelectronic properties of ZnSe1−xTex alloys grown by molecular beam epitaxy over the entire range of compositions. The band-gap energy as a function of the composition presents a minimum at x≂0.65. The main luminescence emission observed at 5 K becomes narrower and closer to the band-gap energy as we increase the Te content. The linewidth and the difference between the emission peak and band-gap energy decrease significantly with increasing x and present a break in the slope at x≂0.65.

Microstructure and optical studies of electron beam evaporated ZnSe1−xTex nanocrystalline thin films

“…This behavior for chemical composition dependence indicates that the optical band gap of the deposited films decreases with increasing tellurium concentration. The decrease in the optical energy gap observed for the results at hand is agree very well with the previously reported results for the same material system [10,11]. The values of the WDD dispersion parameters E o and E d for all composition presented in Fig.…”

“…Among many of the II-VI semiconductors compounds is the ternary alloy ZnSe 1−x Te x which is obtained from the combination of the ZnSe (E g = 2.69 eV) and ZnTe (E g = 2.25 eV) binary compounds. Previously, different spectroscopic techniques like photoluminescence (PL) and photoconductivity (PC) were used to investigate the different optical transitions and the absorption process associated with these transitions in ZnSe 1−x Te x compound [10]. Recently, the bulk sample of ZnSe x Te 1−x has been synthesized using conventional solid state reaction method, in which stoichiometric amount of the binary constituents of ZnSe and ZnTe powders were placed together and heated in a sealed silica tube at 1370 K for 24 h [11].…”

Optical characterization of polycrystalline ZnSe1−xTex thin films using variable angle spectroscopic ellipsometry and spectrophotmetery techniques

“…Among many of the II-VI semiconductors compounds is the ternary alloy ZnSe 1 À x Te x which is obtained from the combination of the ZnSe (E g ¼2.69 eV) and ZnTe (E g ¼2.25 eV) binary compounds. Previously, different spectroscopic techniques like Photoluminescence (PL) and photoconductivity (PC) were used to investigate the different optical transitions and the absorption process associated with these transitions in ZnSe 1 À x Te x compound [4,5]. Recently, the bulk sample of ZnSe x Te 1 À x has been synthesized using conventional solid state reaction method, in which stoichiometric amount of the binary constituents of ZnSe and ZnTe powders were placed together and heated in a sealed silica tube at 1370 K for 24 h [6].…”

Molecular beam epitaxial growth and optical properties of lattice-matched MgxZn1−xSeyTe1−y alloys on InP substrates

“…That is, these materials provide a fully lattice-matched II-VI structure whose active layer and p-type contact layer are lattice matched to the substrate, and which is expected to have a long lifetime. Recently, the epitaxial growth of Zn x Cd 1Ϫx Se, [1][2][3][4][5] Mg 1ϪxϪy Zn x Cd y Se, 2,3,6 ZnSe y Te 1Ϫy , 1,7,8 and Mg x Zn 1Ϫx Se y Te 1Ϫy ͑Ref. 7͒ on InP substrates has been reported.…”