Influence of structural defects on lattice parameter and measured composition of Hg1−xCdxTe epilayers

Mechanical and Thermal Properties

“…These deviations from Vegard's rule were attributed to clusters of two types of theoretically predominant point defects [41]: Hg vacancies or Te antisites, which caused contraction or swelling, respectively, of the crystal lattice. Similar observations were also reported by Mainzer et al [36] for MOVPE-grown material with 0.24 ≤ x ≤ 0.36, where the measured lattice parameters where larger in comparison to the values expected from Vegard's rule, and the observed lattice swelling was attributed to Te-rich regions and high concentrations of Te antisites. Recently, Virt et al [37] measured lattice parameter values of 6.4658 and 6.4661Å for Hg 0.78 Cd 0.22 Te grown by MBE on GaAs (with buffer layers) passivated with polycrystalline and single-crystal CdTe, respectively.…”

“…In a subsequent review, Capper [23] reports a(x ) = 6.4614 + 0.0084x + 0.0168x 2 − 0.0057x 3 Å (8.16) as the expression for the variation of lattice parameter, a, with the composition, x , which was proposed by Higgins et al [3]; and points out that the differences with Brice's near-stoichiometric case and that of Woolley and Ray [24] amount to ±0.001Å or less. Additional data for bulk material [5,[25][26][27], as well as for molecular beam epitaxy (MBE) [28,29,33], liquid phase epitaxy (LPE) [30][31][32]35], and metal-organic vapor phase epitaxy (MOVPE) [36] material are also shown in Figure 8.3, which are in general agreement with each other and with Equation 8.16. In contrast, earlier MOVPE growth of HgTe layers on CdTe by Bhat et al [38] resulted in lattice parameters of 6.454-6.456Å at 1.0-3.5 μm film thickness.…”

Interrelations between defects in the Hg1−xCdxTe epilayers and their measured lattice parameters and composition

“…7,13,15,16 In this study, more than 50 LPE-grown samples were measured with this technique to make statistical analysis of lattice parameter distribution. 7,13,15,16 In this study, more than 50 LPE-grown samples were measured with this technique to make statistical analysis of lattice parameter distribution.…”

Investigation and characterization of Hg1−Cd Te epilayers

“…The energy gap of these ternary compounds is a function of the cadmium content x and temperature T. The precise determination of the composition grading is essential for monitoring the material quality and predicting the photoresponse of Hg 1−x Cd x Te-based infrared detectors. Overall growth of infrared detectors production, makes monitoring of raw material an important part of device fabrication [2].…”