MBE growth of CdSeTe/Si composite substrate for long-wavelength IR HgCdTe applications

For the first time, the ternary alloy CdSexTe1-x(2 1 1) has been grown on Si(2 1 1) substrates using molecular beam epitaxy. The growth of CdSeTe was facilitated using a compound CdTe effusion source and a Se effusion source. The alloy composition (x) of CdSexTe1-x ternary compound was controlled through the Se/CdTe flux ratio. Our results indicate that the quality of CdSeTe decreases as the alloy composition increases, which was possibly due to an alloy disordering effect. A similar trend was observed for the ternary alloy system CdZnTe. However, the alloy disordering effect in CdSeTe is less severe than that in CdZnTe. We have carried out the growth of CdSeTe on Si at different temperatures. Based on our results, we found that the rate of Se incorporation is higher than the rate of Te incorporation as growth temperature increases. As-grown CdSeTe with 4% Se, which is lattice matched to long-wavelength infrared HgCdTe material, exhibits excellent surface morphology, low surface defect density (less than 500 cm(-2)) and low X-ray (full-width at half maximum) of 103 arcsec. (C) 2003 Elsevier Science B.V. All rights reserved.