Author(s)

Mebougna L. Drabo^1,2, Stephen U. Egarievwe^2,3,4, Ifechukwude O. Okwechime³, Dominique E. Jones³, Anwar Hossain⁴, Ralph B. James⁵

¹Department of Mechanical & Civil Engineering, and Construction Management, Alabama A&M University, Normal, AL, USA.
²Department of Electrical Engineering and Computer Science, Alabama A&M University, Normal, AL, USA.
³Nuclear Engineering and Radiological Science Center, Alabama A&M University, Normal, AL, USA.
⁴Department of Nonproliferation and National Security, Brookhaven National Laboratory, Upton, NY, USA.
⁵Science and Technology, Savannah River National Laboratory, Aiken, SC, USA.

Surface defects caused during cutting and polishing in the fabrication of cadmium zinc telluride (CdZnTe) nuclear detectors limit their spectral performance. Chemical treatments are often used to remove surface damages and defects. In this paper, we present the analysis of Te and TeO₂ species on the surfaces of CdZnTe nuclear detectors treated with hydrogen bromide and ammonium-based solutions. The CdZnTe wafers were chemo-mechanically polished in a mixture of hydrogen bromide in hydrogen peroxide and ethylene glycol, followed by a chemical passivation in a mixture of ammonium fluoride and hydrogen peroxide solution. X-ray photoelectron spectroscopy showed significant conversion of Te to TeO₂, thus producing a more chemically stable surface. The resistivity of the CdZnTe samples is in the order of 10¹⁰ ohms-cm. The current for a given applied voltage increased following the passivation and decreased after a 3-hour period. Results from spectral response measurements showed that the 59.5-keV gamma-peak of Am-241 was stable under the same channel for the surface treatment processes.

CdZnTe, Chemical Treatment, Nuclear Detectors, Surface Passivation, XPS

Drabo, M. , Egarievwe, S. , Okwechime, I. , Jones, D. , Hossain, A. and James, R. (2017) Analysis of Te and TeO₂ on CdZnTe Nuclear Detectors Treated with Hydrogen Bromide and Ammonium-Based Solutions. Journal of Materials Science and Chemical Engineering, 5, 9-18. doi: 10.4236/msce.2017.54002.