Comparison of the surfaces and interfaces formed for sputter and electroless deposited gold contacts on CdZnTe

2Citations
Citations of this article
20Readers
Mendeley users who have this article in their library.

Abstract

Cadmium zinc telluride (CdZnTe) is a leading sensor material for spectroscopic X/γ-ray imaging in the fields of homeland security, medical imaging, industrial analysis and astrophysics. The metal-semiconductor interface formed during contact deposition is of fundamental importance to the spectroscopic performance of the detector and is primarily determined by the deposition method. A multi-technique analysis of the metal-semiconductor interface formed by sputter and electroless deposition of gold onto (111) aligned CdZnTe is presented. Focused ion beam (FIB) cross section imaging, X-ray photoelectron spectroscopy (XPS) depth profiling and current-voltage (IV) analysis have been applied to determine the structural, chemical and electronic properties of the gold contacts. In a novel approach, principal component analysis has been employed on the XPS depth profiles to extract detailed chemical state information from different depths within the profile. It was found that electroless deposition forms a complicated, graded interface comprised of tellurium oxide, gold/gold telluride particulates, and cadmium chloride. This compared with a sharp transition from surface gold to bulk CdZnTe observed for the interface formed by sputter deposition. The electronic (IV) response for the detector with electroless deposited contacts was symmetric, but was asymmetric for the detector with sputtered gold contacts. This is due to the electroless deposition degrading the difference between the Cd- and Te-faces of the CdZnTe (111) crystal, whilst these differences are maintained for the sputter deposited gold contacts. This work represents an important step in the optimisation of the metal-semiconductor interface which currently is a limiting factor in the development of high resolution CdZnTe detectors.

Cite

CITATION STYLE

APA

Bell, S. J., Baker, M. A., Duarte, D. D., Schneider, A., Seller, P., Sellin, P. J., … Wilson, M. D. (2018). Comparison of the surfaces and interfaces formed for sputter and electroless deposited gold contacts on CdZnTe. Applied Surface Science, 427, 1257–1270. https://doi.org/10.1016/j.apsusc.2017.08.077

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free