Express Characterization of Crystalline Perfection of CdxHg1−xTe Structures by Reflection Second Harmonic Generation of Probing Radiation

Study of the Crystalline State of MBE (013)HgCdTe/CdTe/ZnTe/GaAs Heterostructure Layers by the Second Harmonic Generation Method

“…The SH polarization components dependence intensity on the mutual orientation of the polarization of excitation radiation in reference to the crystallophysical axes was measured, whereby the experiment recorded the SH polarization parallel to the azimuthally changing linear polarization of the excitation radiation (hereinafter referred to as the azimutal dependence). The experimental and numerical model data for the ideal crystal in a given local area were analyzed to obtain the quantitative information about the crystal state of the subsurface layer, its orientation and the growing layers orientation rotation within the plane and the growth direction, as well as a number of other characteristics with an error no worse one degree [26][27][28][29][34][35][36][37][38][39][40]. The crystal state of the MCT layers was measured by azimuthal SH signal intensity dependence measurement with layerby layer etching.…”

“…The SH calculation using the non-linear susceptibility tensor χ x y z (ω) in the crystals of sphalerite or zinc blende (international classificationclass 43m) is described in detail in [30,31]. When comparing the calculation and experimental results of the azimuthal SH signal dependences in a specific geometry and for specific crystal slices, numerical modelling is applied [25][26][27][28][29][32][33][34].…”

“…The analysis of the curves behavior of the model azimutal dependences of the SH signal with the variation by the angles θ and ϕ near the (013) orientation showed (see studies [26][27][28][29]) that these dependences are very sensitive to small deviation from the angle ϕ at the normal beam incident. That is why the laboratory test bench was used to perform the normal incidence of the laser radiation of frequency ω to the studied sample by simultaneously rotating its polarization plane (azimuthal angle) within the range from 0 to 359 • and recording the intensity reflected second harmonic signal with the polarization parallel to the polarization of the laser radiation.…”

“…Taking into account a unique determinability of the absolute orientation for non-centrosymmetric crystals in relation to the shear plane by the second harmonic generation of the probing laser radiation, we have examined the rotation of the orientation of the (013)GaAs substrates and the (013)CdTe layers when growing on the (013)ZnTe/GaAs substrates within the growth plane by the second harmonic generation (SHG) [26][27][28][29]. It was shown that for the CdTe/ZnTe/GaAs(013) structures the rotation within the growth plane was from 3 to 8 angl.…”

“…The second harmonic generation (SHG) is a faster and more convenient method in comparison with the electron and X-ray diffraction methods in the studies for obtaining the express non-destructive information, which supplements the application of traditional electron, X-ray and other diffraction methods [26][27][28][29][34][35][36][37][38][39][40].…”