Optimization of the structural properties of Hg1-x CdxTe (x=0.18-0.30) alloys: Growth and modeling

The conditions for the metalorganic molecular beam epitaxial growth of Hg1-xCdxTe (x = 0.18-0.32) alloys at very low growth temperatures (T less than or equal to 150 degrees C) have been optimized by correlating the surface properties and crystalline perfection with the incident Hg flux. A window for growth has been defined for x = 0.18, 0.23, and 0.32. A thermodynamic model has been developed to account for void formation. A neural net model has been used for the first time to model the dependence of void density on the Hg flux and the x-ray rocking curve widths on growth parameters. The combination of these two complementary modeling techniques allows for a flexible process optimization to be carried out with a minimum effort spent in calibration runs.