High pressure x-ray diffraction and extended x-ray absorption fine structure studies on ternary alloy Zn1−xBexSe

Abstract

International audienceThe ternary semiconductor alloy Zn1−xBexSe has been studied under high pressure by x-ray diffraction and extended x-ray absorption fine structure EXAFS at the Zn and Se K-edge in order to determine the bulk and bond-specific elastic properties. Our measurements on samples with x =0.06–0.55 show pressure induced phase transformation from zinc blende to NaCl. The phase transformation pressure increases linearly with x. Murnaghan equation of state fitting to the data yields the unit cell volume at ambient pressure and bulk modulus, both of which follow the Vegard's law. Nearest neighbor bond distances derived from EXAFS do not show sharp phase transition except for x=0.06. Bond modulus derived for the Zn–Se bonds shows them to be apparently stiffer than the bulk alloy, which is nontrivial. This tendency increases with increasing x and a strong positive bowing from the Vegard's law is observed. We attribute the observed anomalies to the contrastingly different properties of the two components ZnSe and BeSe

Near-forward/high-pressure-backward Raman study of Zn1 − x Be x Se (x ~ 0.5) - evidence for percolation behavior of the long (Zn―Se) bond

“…The angle‐sensitive features in our near‐forward Raman spectrum displayed in Fig. b are C and D. By analogy with the near‐forward Raman spectra of ZnSe 1 − x S x alloys, C and D are assigned in terms of the PP − and Int‐PP modes of Zn 0.47 Be 0.53 Se. Schematically, the dispersion of C/ PP − is expected to look like that of pure ZnSe, while D/Int‐PP is expected to exhibit a characteristic S‐like dispersion asymptotically determined by the wavenumber (~450 cm −1 ) in the large‐ q limit (backscattering regime) and by the LO Zn − Se (~250 cm −1 ) wavenumber when approaching Γ ( q = 0) …”

“…We mention that the pressure remains below that corresponding to the zinblende → rocksalt transition of Zn 0.47 Be 0.53 Se, extrapolated to ~35 GPa from Ref. (see Fig. 3 therein).…”

Ambient Zinc K-Edge Extended X-Ray Absorption Fine Structure Studies on Solid Solution Hardening of the Ternary Alloys

“…Nonetheless, the data quality does not allow us to go for further NNNN radial peak �tting in real space, which is feasible only when the EXAFS measurements are taken at low temperatures [22]. e corresponding radial distribution functions of the NN distance in the Zn−Se single scattering paths are calculated for all the assorted compositions.…”

EXAFS studies of novel impulsive hardening in the Be–Zn–Se semiconductor alloys

“…Lots of present scientific endeavors are therefore dedicated towards the objective of studying the localized nature of the hardening and the bond character in this new class of mixed alloy mainly by using the local structural probes like extended X-ray absorption fine structures (EXAFS), however the research claims are often contradictory in nature due to the complicated procedure of the fine structure extraction. 10 In this report, we present our studies on the EXAFS measurements performed on a set of compositionally vivid (0.06 < x < 0.55) ternary semiconductor alloys (Be x Zn 1−x Se) at the Zn-K X-ray absorption edge. Using our results we also try to explain the nature of hardening that takes place in the ternary, and the contemporary trends therein.…”