Study of surface passivation and contact deposition techniques in CdZnTe X-Ray and gamma-ray detectors

• Main Authors: Jones, Dominique E., Egarievwe, Stephen U., Hossain, Anwar, Okwechime, Ifechukwude O., Drabo, Mebougna L., Hall, JaQueeta, Adams, Aaron L., Babalola, Stephen O., Camarda, Giuseppe S., Bolotnikov, Aleksey E., Wing Chan, James, Ralph B.
• Format: Conference Proceeding
• Language: English
• ISSN: 1082-3654; 2577-0829
• DOI: 10.1109/NSSMIC.2012.6551942

Passivation and improved contact deposition techniques are known to reduce the surface leakage current and decrease noise levels of CdZnTe X-Ray and gamrna-ray detectors by improving their spectral energy resolutions. This paper presents a comparative study of surface passivation process in CdZnTe X-Ray and gamma-ray detectors. The experimental study compares three surface passivation processes: mechanically polished with a O.9μm Alumina Powder (AI 2 O 3 ) finishing; mechanically polished with a O.9μm Alumina Powder (AI 2 O 3 ) and etched with HBr + H 2 O 2 solution for 2 minutes; mechanically polished with a O.9,.m Alumina Powder (AI 2 O 3 ) and chemomechanically polished with bromine-methanol-ethylene glycol solution. The results show that chemo-mechanical polishing with bromine-methanol-ethylene glycol solution proved to be the best method out of the three for reducing surface leakage current. The preliminary results of aging studies on H 2 O 2 (Hydrogen Peroxide), NH4F (Ammonium Fluoride) + H 2 O 2 + H 2 O and (NH4hS (Ammonium Sulfide) passivation agents are also presented.