Development of High Quality and Large (3 & 4 Inch Diameter) Cd[sub 1-x]Zn[sub x]Te/Si Substrates Lattice-Matched to Hg[sub 1-x]Cd[sub x]Te

The fabrication of large format, long wavelength (LWIR) mercury cadmium telluride based focal plane arrays (FPAs) is highly desirable for Air Force applications such as satellite power and array cooling reduction along with higher resolution. However, the development of large FPAs has been seriously impeded by the limited size of commercially available bulk Cd{sub 1-x}Zn{sub x}Te substrates. In this project we propose to develop high-quality (defect density less than 5 x 10{super 5} defects per cm{super 2}) high purity (less than 10{super 14} active impurities per cm{super 3}) 3-inch diameter (extended to 4-inch in Phase II) Cd{sub 1-x}Zn{sub x}Te/Si substrates lattice-matched to Hg{sub 1-} Cd{sub x}Te. Si substrate has been selected because of its low cost, large area availability and mechanical strength. In addition, the absence of thermal expansion mismatch between substrate and readout circuits of FPAs both in silicon will pave the way for larger format arrays. These substrates will be grown by molecular beam epitaxy (MBE) in the (111)B and 211(B) orientations which are the preferred orientations for HgCdTe growth by liquid phase epitaxy (LPE) and MBE respectively. Photoluminescence will be implemented as a cost-effective screening technique to detect low impurity concentration levels.