TY - JOUR
T1 - Effects of oxygen plasma treatment on Cd1−xZnxTe material and devices
AU - Brovko, A.
AU - Amzallag, O.
AU - Adelberg, A.
AU - Chernyak, L.
AU - Raja, P. V.
AU - Ruzin, A.
N1 - Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2021/7/11
Y1 - 2021/7/11
N2 - Surface passivation in detectors is designed to improve the performance and stabilize the characteristics over time and ambient. In Cd1−xZnxTe radiation detectors, oxidation by plasma is a well-known passivation method, but its physics is not fully understood. This study focuses on the macroscopic and microscopic effects of plasma treatment. It is shown that plasma oxidation before contact deposition causes a considerable decrease in the device's dark current and that this reduction is in a strong correlation with the lowering of the surface potential. X-ray photoelectron spectroscopy (XPS) measurements revealed a significant increase in TeO 2 fraction on the plasma-treated surface. The main conclusion of this study is that the plasma-related effects are not confined to the surface layer. Furthermore, the deep penetration of plasma treatment byproduct takes place over long time periods, which may lead to variations in device characteristics. The effects were corroborated by several characterization techniques. DC current–voltage measurements combined with layer-by-layer stripping indicate plasma signature deep into the bulk. Transient current technique (TCT) results demonstrate that the plasma treatment affects the electric field distribution millimeters into the bulk. Photo-induced current transient spectroscopy (PICTS) and thermoelectric emission spectroscopy (TEES) measurements reveal plasma-related traps in-depth of the CdZnTe crystals.
AB - Surface passivation in detectors is designed to improve the performance and stabilize the characteristics over time and ambient. In Cd1−xZnxTe radiation detectors, oxidation by plasma is a well-known passivation method, but its physics is not fully understood. This study focuses on the macroscopic and microscopic effects of plasma treatment. It is shown that plasma oxidation before contact deposition causes a considerable decrease in the device's dark current and that this reduction is in a strong correlation with the lowering of the surface potential. X-ray photoelectron spectroscopy (XPS) measurements revealed a significant increase in TeO 2 fraction on the plasma-treated surface. The main conclusion of this study is that the plasma-related effects are not confined to the surface layer. Furthermore, the deep penetration of plasma treatment byproduct takes place over long time periods, which may lead to variations in device characteristics. The effects were corroborated by several characterization techniques. DC current–voltage measurements combined with layer-by-layer stripping indicate plasma signature deep into the bulk. Transient current technique (TCT) results demonstrate that the plasma treatment affects the electric field distribution millimeters into the bulk. Photo-induced current transient spectroscopy (PICTS) and thermoelectric emission spectroscopy (TEES) measurements reveal plasma-related traps in-depth of the CdZnTe crystals.
KW - CdZnTe, CZT, II–VI group detectors
KW - Gamma detectors
KW - Room temperature detectors
KW - X-ray detectors
UR - http://www.scopus.com/inward/record.url?scp=85104910058&partnerID=8YFLogxK
U2 - 10.1016/j.nima.2021.165343
DO - 10.1016/j.nima.2021.165343
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AN - SCOPUS:85104910058
SN - 0168-9002
VL - 1004
JO - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
JF - Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
M1 - 165343
ER -