An investigation of the properties of HgCdTe films grown by MBE and devices made from such films are reported. Through the precise control of growth conditions and the screening of the Zn component of CZT(211)B substrates, high-quality HgCdTe films were successfully deposited onto the CZT(211)B substrates and characterized by x-ray diffraction rocking curve analysis and etch pit density analysis. X-ray rocking curve (422) reflection full-width at half-maximum (FWHM) of less than 15 arcsec was obtained for Hg 0.7 Cd 0.3 Te epitaxial films, and etch pit density (EPD) of about 2 × 10 4  cm −2 was observed. At the same time, the relationship between the FWHM of the x-ray double-crystal rocking curve and EPD was confirmed. By optimizing the pretreatment process of the CZT(211)B substrate, a further significant reduction in HgCdTe macrodefect densities to 54 cm −2 to 1000 cm −2 was observed on CdZnTe, including occasional occurrences of very few or no large "void clusters" that are often observed. Planar p-on-n HgCdTe mid-wave infrared (MWIR) focal plane arrays (FPAs) were fabricated based on MBE in situ indium doping and arsenic ion implantation technology. The temperature-dependent performance of planar p-on-n MWIR FPAs shows that the device has the ability to operate at high temperature of about 140 K with high performance.