Numerical Analysis of Piezoelectric Spectra of Zn1-x-yBexMnySe Mixed Crystals

Abstract

This article presents the numerical analysis of the amplitude and phase piezoelectric spectra of a group of mixed crystals of the Zn 1−x−y Be x Mn y Se type. After growth treatment of mixed crystals, such as grinding, polishing, and etching, some surface defects have been created whose energy levels are in the region of the band gap of the material. The lower the concentration of these defects is, the smaller amplitude of the photothermal signal in this energy region is expected and the higher the quality of such a crystal surface is. This article focused on the study of the application of photothermal piezoelectric method for investigation of the surface energy levels and their corresponding absorption bands in the energy-gap region of the material.

Determination of the Exciton Binding Energy Using Photothermal and Photoluminescence Spectroscopy

“…The necessity of such an assumption arises from results of previous studies carried out for II-VI binary crystals, as well as for mixed ternary and quaternary solid solutions [9,[11][12][13][14]. In general, to interpret the PPT signal, one must consider the periodical temperature field generated in the sample caused by the absorption of the intensity modulated periodical optical radiation.…”

“…Samples were illuminated with an intensity-modulated beam of light of a xenon lamp (Cermax 300 W) after passing through the prism monochromator. The piezoelectric signal was detected with a lock-in phase selective amplifier (Stanford SR 510) at RT in the rear experimental configuration [9]. The PL setup consisted of the laser (HeCd, 325 nm, 20 mW); closedcycle helium cryostat with the sample; temperature controller (LakeShore 331); and the spectrometer (MicroHR Horiba Jobin Yvon) equipped with diffraction gratings, filter wheel, and the thermoelectrically cooled CCD camera (Synapse Horiba Jobin Yvon).…”

Photothermal Investigation of Surface Defects of Pure Semiconducting A2B6 Materials

“…The temperature distribution in the sample is the basis for the finding of the theoretical amplitude and phase photoacoustic spectra. It is given by the J-A theory and that modified by Maliński et al [11]. This method was successfully used for the interpretation of PA spectra for A2B6 mixed crystals [11][12][13].…”

“…It is given by the J-A theory and that modified by Maliński et al [11]. This method was successfully used for the interpretation of PA spectra for A2B6 mixed crystals [11][12][13]. It gives very good agreement with the experimental data if one assumes the presence of defects in the sub-bandgap region but is not so accurate in the region very close to the value of the energy gap of a semiconducting material.…”

“…One of the thermal methods is the piezoelectric (PZE) photothermal technique which was theoretically described by Jackson and Amer (J-A) [9] and by Blonskij et al [10]. The J-A theory was successfully used to investigate the properties of A2B6 mixed crystals [11][12][13].…”