Comparison of mercury cadmium telluride LPE layers growth from Te-rich solution on (111)Cd0.95Zn0.05Te and (211)Cd0.95Zn0.05Te

摘要

Abstract: The quality of Hg$-1-x$/Cd$-x$/Te epitaxial layers made of is strongly dependent on the crystalline properties of the substrate. The chemical compatibility and the small lattice mismatch between Hg$-1-x$/Cd$-x$/Te and CdTe have been primary motivation for choosing CdTe as a substrate for Hg$-1-x$/Cd$- x$/Te epitaxial layers. Nevertheless, the most important issue of epitaxial layers on the CdTe substrate is conditioned by lattice mismatch. In order to eliminate these problems we have replaced the CdTe substrate by Cd$-0.95$/Zn$-0.05$/Te which are lattice-matched to the Hg$-1-x$/Cd$-x$/Te compound. In this work we conduct systematic experimental study of the two type of substrates: (111)B Cd$-0.95$/Zn$-0.05$/Te and (211)B Cd$-0.95$/Zn$-0.05$/Te. The (111)-oriented substrate remains attractive as the growth results in flat, featureless surfaces with excellent interfaces with lattice matched substrate. The (211)-oriented substrates combine the structural quality of (100) including the absence of twinning with the flat topography of (111)-oriented wafers. The Hg$-1-x$/Cd$-x$/Te epilayers were grown from Te-rich solutions on (111)Cd$- 0.95$/Zn$-0.05$/Te and (211)Cd$-0.95$/Zn$-0.05$/Te by a horizontal tipping liquid phase epitaxy technique. Characterization of the epilayers involved FTIR spectroscopy to determine both its thickness and composition. LPE film surface morphology was examined using microscope equipped with Nomarski phase contrast and atom force microscopy. The as- grown or annealed layers were measured by Hall effect at 300 and 77 K using Au or indium contacts. !11