Analysis of Defects on Chemically-Treated CdZnTe Surfaces

Abstract

In this work, we focused on investigating the various defects that extend into the near-surface region of CdZnTe (CZT) crystals, and on exploring processing techniques for producing a smooth, non-conductive surface that is ideal for growing thin films and depositing contacts. We determined the surface's features and the chemical species present using atomic-force microscopy, x-ray photoelectron spectroscopy, and scanning electron microscopy (SEM), coupled with energy-dispersive spectroscopy. We revealed crystallographic defects, e.g., sub-grains and dislocations on the CZT crystals' surfaces, after employing selected chemical etchants, and then characterized them using optical microscopy, SEM and optical profilometer. Our experimental data imply that the surface defects and chemical species induced by chemical processing may alter the material's interfacial behavior, and ultimately significantly influence the performance of radiation detectors.