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Effect of chlorination on the TlBr band edges for improved room temperature radiation detectors (Phys. Status Solidi B 6/2015)
Author(s) -
Varley J. B.,
Conway A. M.,
Voss L. F.,
Swanberg E.,
Graff R. T.,
Nikolic R. J.,
Payne S. A.,
Lordi V.,
Nelson A. J.
Publication year - 2015
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201570337
Subject(s) - materials science , etching (microfabrication) , band gap , isotropic etching , alloy , detector , ionizing radiation , radiation , hydrochloric acid , optoelectronics , analytical chemistry (journal) , irradiation , nanotechnology , chemistry , optics , composite material , physics , metallurgy , layer (electronics) , chromatography , nuclear physics
The energy resolution of room temperature radiation detectors is limited by material properties such as the atomic number of the constituent atoms, band gap, electrical transport coefficients and crystalline purity, which critically affect both the stopping distance of ionizing radiation and the carrier collection from the material. Thallium bromide (TlBr) possesses properties that satisfy these criteria and has emerged as a leading candidate for next‐generation detectors, but it currently suffers from degradation phenomena that limit long‐term performance. Chemical surface treatments can drastically improve the lifetime of TlBr‐based devices, with hydrochloric acid etching in particular shown to increase longevity, but the exact role of these treatments has remained poorly understood. Using a combination of experimental and theoretical methods, Varley et al. (pp. 1266–1271 ) address how these treatments influence the surface composition and the underlying electronic structure. Their results indicate that the etch treatment forms a TlBr x Cl 1‐x alloy at the surface whose composition is sensitive to the chemical conditions. The surface alloy suppresses hole injection but may also provide several other beneficial functions that will require further study.