Charge transport properties in CdZnTe detectors grown by the vertical Bridgman technique

Abstract

Hard x-ray response of pixellated CdZnTe detectorsPresently, a great amount of effort is being devoted to the development of CdTe and CdZnTe (CZT) detectors for a large variety of applications such as medical, industrial, and space research. We present the spectroscopic properties of some CZT crystals grown by the standard vertical Bridgman method and by the boron oxide encapsulated vertical Bridgman method, which has been recently implemented at IMEM-CNR (Parma, Italy). In this technique, the crystal is grown in an open quartz crucible fully encapsulated by a thin layer of liquid boron oxide. This method prevents contact between the crystal and the crucible, thereby allowing larger single grains with a lower dislocation density to be obtained. Several mono-electrode detectors were realized, with each having two planar gold contacts. The samples are characterized by an active area of about 7 mm  7 mm and thicknesses ranging from 1 to 2 mm. The charge transport properties of the detectors have been studied by mobility-lifetime (l  s) product measurements, carried out at the European Synchrotron Radiation Facility (Grenoble, France) in the planar transverse field configuration, where the impinging beam direction is orthogonal to the collecting electric field. We have performed several fine scans between the electrodes with a beam spot of 10 lm  10 lm at various energies from 60 to 400 keV. In this work, we present the test results in terms of the (l  s) product of both charge carriers.

Fabrication and testing of antimony doped bismuth tri-iodide semiconductor gamma-ray detectors

“…The value of µτ product can vary from detector to detector since it depends on the concentration of internal defects and traps. Taking this into consideration the estimated electron µτ product for the Sb doped BiI 3 is comparable to that reported for HgI 2 (~ 10 -4 -10 -3 cm 2 /V) and TlBr (~ 10 -4 cm 2 /V), but is lower than that reported for CZT (~ 10 -3 cm 2 /V) [24], [25], and [26]. The low µτ product of the electrons could be attributed to the presence of internal defects and trapping sites within the crystal.…”

A digital approach for real time high-rate high-resolution radiation measurements

“…We performed X-ray spectra measurements, at both low and high ICRs, with a thin planar CdTe detector [20]. As well known, thin CdTe/CdZnTe detectors (1-2 mm thick) are very appealing for X-ray spectroscopy in the 1-100 keV energy range [40][41][42][43][44][45][46][47]. We used a planar CdTe detector (XR100T-CdTe, S/N 6012, Amptek, USA) with a thickness of 1 mm (absolute efficiency of 64% at 100 keV) and equipped with a resistive-feedback CSP.…”

High-rate dead-time corrections in a general purpose digital pulse processing system

“…The gain of the CSP is 0.82 mV keV À1 and the rise time of the CSP output pulses is around 60 ns (59.5 keV X-rays). As is well known, CdTe/CdZnTe detectors (1-2 mm thick) are very appealing for X-ray spectroscopy in the energy range 1-100 keV (Auricchio et al, 2011;Del Sordo et al, 2009;Owens, 2006;Takahashi & Watanabe, 2001;Turturici et al, 2014Turturici et al, , 2015. The high-rate spectroscopic abilities of the DPP system, connected to the CdTe detector, were investigated in our previous works (Abbene et al, 2013a,b;.…”