A Scanning Probe Microscopy Study of Cd1−x Zn x Te

Abstract

The effects of several ex vacuo methods used in the surface preparation of Cd 1Àx Zn x Te (CZT) have been studied using noncontact atomic force microscopy, scanning tunneling microscopy, and scanning tunneling spectroscopy. Preparation techniques include mechanical lapping, hydroplane bromine-methanol polishing, and in vacuo annealing. The morphology, electrical homogeneity, and local density of states (LDOS) have been studied for each preparation method. Impurities and oxides quickly form on the surface after each preparation method. Annealing in ultrahigh vacuum causes the surface electronic structure to become inhomogeneous whilst the LDOS suggests a compositional change from an oxide surface to p-type CZT.

As-Received CdZnTe Substrate Contamination

“…CdZnTe surfaces are vulnerable to polishing damage in the form of surface scratches. 7 As can be observed from all three images, the final polishing step leaves scratches and residual polishing grit on the (112)B surface. The 'deep' polishing scratches are 0.3 nm in depth and 0.1 lm wide.…”