Characterization of Zn_0.95‐xBe_x Mn_0.05Se mixed crystals by photoluminescence and contactless electroreflectance

Abstract

Temperature‐dependent photoluminescence (PL) and contactless electroreflectance (CER) measurements of Zn0.95‐xBexMn0.05Se mixed crystals with different Be content (0 ≤ x ≤ 0.26) grown by the modified high pressure Bridgman method has been carried out in the temperature range 15–300 K. The peak positions of band‐edge exciton features in the PL spectra are slightly shifted towards lower energies as compared to the corresponding transition energies obtained from CER data. The observed increases of the CER‐PL shift with the increasing of Be content are explained by the increasing compositional disorder causing the smearing of the band‐edge energies. The excitonic line broadening for the samples with larger Be/Zn ratio are attributed in part to the alloy scattering effects and also to the poorer crystalline quality of the samples with higher content of Be. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Optical characterization of Zn0.35Cd0.44Mg0.21Se crystalline alloy by polarization‐dependent contactless electroreflectance measurements

“…Figure 4 shows the temperature evolution of the nearband-edge PL spectra of WZ-Zn 0.35 Cd 0.44 Mg 0.21 Se sample. Similar to most of the other II-VI compounds [21,22], at low temperature, the PL spectrum consists of a relatively sharp peak (an exciton line denoted as X) followed by a broader "edge-emission" feature due to radiative recombination of shallow donor-acceptor pairs (DAP) and a broad deep level (DL) band. The values of energy position and full width at half maximum (FWHM) of the first peak X at 10 K were determined to be 2.524 eV and 29 meV, respectively.…”