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HgCdTe films grown by Molecular Beam Epitaxy (MBE) are essential for creating high-performance Infrared Focal Plane Arrays (IRFPAs) like dual band detectors, High Operating Temperature (HOT) detectors, and Avalanche Photodiode (APD) detectors. CdZnTe is recognized as the optimal substrates for growing high crystal quality HgCdTe due to its lattice matching, which is adjusted by selecting the Zn mole fraction. If the Zn mole fraction in CdZnTe substrates falls outside the ideal range, it may lead to an increase in dislocation density in HgCdTe films, thereby adversely affecting the performance of the device. A proposed method has been introduced for designing a lattice-matching buffer layer between CdZnTe substrates and HgCdTe films. Growth of HgCdTe on CdZnTe substrates with an unsuitable Zn mole fraction was conducted with and without a lattice-matching buffer layer. Results showed that the dislocation density of the HgCdTe film obtained on CdZnTe substrates with an unsuitable Zn mole fraction usually exceeds 1×106 cm-2. However, as expected, the presence of a lattice-matching buffer layer significantly reduced the dislocation density of HgCdTe films. The dislocation density can be effectively controlled within 3×105 cm-2, with a mean value around 1×105 cm-2 . By doing so, the allowable range of Zn mole fraction in substrates for producing high-quality HgCdTe films can be widened, which holds significant engineering implications for the manufacturing of MBE HgCdTe.
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