TRANSIENT-BEHAVIOR OF HG1-XCDXTE FILMS DEPOSITED ON (100)CDTE SUBSTRATES BY CHEMICAL-VAPOR TRANSPORT

The growth history of Hg1-xCdxTe films deposited on (100) CdTe substra tes by chemical vapor transport (CVT) has been studied, for the first time, by using a transient growth technique. The observed morphologica l evolution of Hg1-xCdxTe films deposited at 545 degrees C shows a tra nsition behavior from three-dimensional (3D) islands to two-dimensiona l (2D) layer growth. The experimental results indicate that the so-cal led critical time needed for the above morphological transition is abo ut 1h under present experimental conditions. Based on the chemical bon ding properties of Hg1-xCdxTe, and on the behavior of the morphologica l transition, the Stranski-Krastanov growth mode is suggested for the epitaxial growth system. The time dependence of the growth thickness, of the growth rate (R(100)) along the [100] direction, and of the surf ace composition all reveal a transient behavior. These are related to the nature of the Hg1-xCdxTe/(100)CdTe heterojunction and to the surfa ce reactions. Comparison of the growth rates and of the total mass dep osited as a function of time shows the relationship between epitaxial growth and mass flux of the Hg1-xCdxTe-HgI2 chemical vapor transport s ystem.