Fabrication and characterization of CdZnTe pixel detector

The CdZnTe single crystal was fabricated into a pixel detector and its energy spectroscopic response and uniformity were systematically characterized. The resistivity and product of carrier mobility and lifetime were calculated by I-V and energy spectroscopic response test. The distribution of Te inclusions was observed with IR transmission imaging. A 8×8 pixel electrode was fabricated employing photolithography, lift-off and electrode deposition techniques. Then, the detector was bonded to the readout PCB board with conductive silver adhesives using stencil printing and patching techniques. The testing results show that the maximum leakage current of single pixel is less than 0.7 nA. The energy resolution for ²⁴¹Am 59.5keV is up to 5.6%, which is better than that of planar detector. The analysis of the influence of Te inclusions on leakage current and energy spectroscopic response predicts that the aggregation of Te inclusions will increase the leakage current and in consequence reduce the energy resolution of the detector.