Heteroepitaxy of CdTe on Si substrates in view of infrared and x-ray detection

CdTe can be grown directly on silicon substrates by Molecular Beam Epitaxy. On Si(001), CdTe grows in the (111)B orientation. The homo-orientation on Si(001), Si(111) and Si(211) can be obtained if a buffer ZnTe epilayer is grown prior to CdTe growth. A systematic study of the growth of CdTe(111)B on Si(001) surface with different atomic step structures, defined by the miscut tilt angle (theta) and the tilt direction (phi) , has been carried out. Double domain and twin formation is very sensitive to tilt parameters. When growth conditions are optimized, single domain twin free layers are obtained with suitable tilt values. The best films which exhibit double crystal X-ray rocking curve FWHM of 60 arcsec have for tilt parameters (theta) equals 1 degree(s) and (phi) equals 30 degree(s). The heterointerface formation has been studied by photoelectron spectroscopy with synchrotron radiation. It was found that in the very first step of the growth, up to one monolayer of Te is absorbed on Si(001).