The results on composition control and surface defect study of molecular beam epitaxial (MBE)-grown Hg1-xCdxTe are described. In the long wavelength regime, the standard deviation in x values determined by FTIR and ellipsometry measurements was 0.013. Good composition reproducibility was achieved. A variety of surface defects was observed and their origins are discussed. The optimized growth window for obtaining a good morphological surface was determined. By careful efforts in substrates preparation as well as growth control, the averaged density of surface defects (>2 mum) for 2 in 10 mum-thick HgCdTe wafers was determined to be 300 cm(-2). LW 256 x 1 linear focal plane arrays were fabricated on MBE-grown HgCdTe epilayers. An average detectivity D-lambda* of 3.5 x 10(10)cm Li root Hz W-1 with a non-uniformity factor of 8.8% was obtained.