Lead tin selenide(211)/cadmium telluride(211)boron/silicon(211) interfaces
Abstract
The Si(211) reconstruction was studied after normal molecular beam epitaxial (MBE) preparation procedures and the subsequent reconstruction after arsenic deposition. The effect of this reconstruction on the CdTe and CdTe/PbSnSe interface is examined. Implications of the strain between the epitaxial materials were explored and for the first time, PbSnSe(211) on CdTe(211)B/Si(211) substrates have been grown. Material quality of PbSnSe on CdTe/Si is compared to material grown on bulk BaF2(111). Samples have been characterized using Low Energy Electron Diffraction (LEED), Nomarski, Fourier Transform Infrared Spectroscopy (FTIR), Photoluminescence (PL), Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). LEED images indicate the (211) surface is unstable and facets. The degree of faceting and the magnitude of disorder is dependent on preparation procedures. Arsenic deposition beginning at high temperatures controls silicon faceting into a series of 19.2 A rows. This configuration reduces both tetragonal and shear strain at the CdTe/Si interface. At the PbSnSe/CdTe interface the (211) orientation allows the thermal mismatch between silicon and PbSnSe to be accommodated within the first 5 nm of the interface though a network of glide dislocations. It was also observed that the threading dislocations were greatly reduced and gettered to the (111) [01¯1] glide system when compared to the (111) orientation. This allowed the PbSnSe to be grown without cracking even after several thermal cycles.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- 2007
- Bibcode:
- 2007PhDT........46F