Optical and Structural Properties of Zn_1-xBe_xSe Mixed Crystals

Abstract

Optical and structural properties of Ζn 1 -x Bex Se bulk crystals in the range of composition 0 _ < x < 0.41 have been studied. These crystals were grown by Bridgman method under an argon overpressure. Transmission, absorption, photoluminescence and photoacoustic spectra as a function of composition were investigated. It has been found that the crystal structure is of sphalerite type. The crystal quality increases when the crystallization process of the same boule is performed more than once. In the investigated composition range the lattice constant decreases and the energy gap increases with increasing beryllium content. From photoluminescence measurements the excitonic energy gap about 3.64 eV at 40 K was estimated for the highest obtained Be concentration (x = 0.41).PACS numbers: 78.55. Et, 62.65.+k Mixed crystals of wide gap Il-VI compounds with Be chalcogenides are of particular interest because of their potential applications in constructing visible and UV lasers. The Zn1-xBexSe has a much higher degree of covalent bonding as compared to other (more ionic) wide gap II-VI compounds which modifies its mechanical properties [1]. This is expected to result in considerable lattice rigidity, a very important factor for reducing defects migration and multiplication. Until now, the published papers were concerned in thin films [2] but the fundamental properties of mixed Ζn 1 -x BeSe bulk crystals remain unknown for the wide range of composition. Some preliminary results for 0 < x < 0.17 have been recently published in Ref. [3].Zn 1 -x Bex Se crystals were grown by Bridgman method under an argon overpressure in the range of composition 0 < x < 0.41 using a powder mixture of (309)

Photoelectric and photothermal investigations of Zn1‐x‐yBexMnySe solid solutions

“…This is in conformity with the observation, that increasing Be and Mn concentration in Zn 1-x-y Be x Mn y Se causes increase the lattice rigidity of the material [23]. …”

Growth and properties of Zn1–x –yBex Mny Se crystals

“…It was observed that for concentration of beryllium larger that about 0.1 only yellow emission is observed in the temperature range from 34 K to room temperature. This is in agreement with the observations for Zn 1-x Be x Se crystals grown by the same method [3] where the intensity of exciton emission decreased with increasing of Be content. For this reason, determination of the energy gap from lumines- cence data is not possible for crystals with high Mn content.…”