Performance of a new schottky CdTe detector for hard X-ray spectroscopy

We report a significant improvement of spectral properties of a cadmium telluride (CdTe) detector. This was accomplished via the use of a high quality CdTe crystal, where high Schottky barrier for the holes oil a CdTe surface was formed by using a low work-function metal, indium. With a 2x2 mm(2) detector at a thickness of 0.5 mm, the leakage current is measured to be 0.7 nA at room temperature (20 degrees C) and below 1 pA at -70 degrees C for 400 V bias voltage. The low leakage current allows us to operate the detector at a higher bias voltage than for previous CdTe detectors. The energy resolution we achieved at room temperature is 1.1-2.5 keV FWHM from the energy range of 2 keV to 150 keV at 20 degrees C without any charge-loss correction electronics. At -70 degrees C we obtained all energy resolution of 1.0 keV FWHM at 122 keV and 2.1 keV FWHM at 662 keV.