Low-temperature photoluminescence of detector grade Cd1−xZnxTe crystal treated by different chemical etchants

Abstract

Low-temperature photoluminescence (PL) spectra of detector grade Cd1−xZnxTe (x=0.1) have been measured to obtain information about shallow level defect concentration introduced during mechanical polishing and chemical etching processes. We present here a comparative PL study of Cd0.9Zn0.1Te crystals treated by different chemical solutions used for nuclear detector surface treatment. The results show that the 5% Br–MeOH+2%Br–20% lactic acid in ethylene glycol treatment combines the advantages of bromine and lactic acid for chemical etching and results in the best surface condition, as evidenced by the largest I(D0,X)/Idef intensity ratio and the narrowest full width at half-maximum of the main peak (D0,X). Changes in the surface morphology were also analyzed by atomic force microscopy and correlated with the PL results. Current–voltage (I–V) curves and the room-temperature 55Fe spectral response of the sample etched by the best treatment are also presented and discussed.

A multi-technique characterization of electroless gold contacts on single crystal CdZnTe radiation detectors

“…It has previously been reported such variation in interface depth was related to polishing damage and associated sub-surface strain [27], however this variation has also been observed in chemo-mechanically polished surfaces following electroless deposition but not following sputter deposition [28]. Chemical or chemo-mechanical etching, with agents such as bromine methanol, has been demonstrated to remove polishing induced surface damage [29][30][31]. It was concluded that the variation observed in the present study was the result of a localized difference in the rate of reaction of the electroless process.…”

Performance of CdZnTe detectors passivated with energetic oxygen atoms

“…Detectors are often treated with etchants, such as bromine/methanol, to remove damage caused by polishing and to increase the planarity (smoothness) of CZT crystals (Chen, 1996 andChen, 1997).…”

Material properties of large-volume cadmium zinc telluride crystals and their relationship to nuclear detector performance

“…There are several papers reporting details of fabrication processes and their effects on detector response. 14,34,[39][40][41][42][43][44] The standard process used today for chemically etching CZT surfaces involves surface treatment with a Br-methanol solution. This process leaves behind a nonstoichiometric surface which is believed to be Terich.…”