High-resolution Schottky CdTe diode detector

We describe recent progress on the use of Schottky CdTe diode detectors for spectrometry. The low leakage current of the CdTe diode allows us to apply a much higher bias voltage than was possible with previous CdTe detectors. For a relatively thin detector of 0.5-1 mm thickness, the high bias voltage results in a high electric field in the device. Both the improved charge-collection efficiency and the low-leakage current lead to an energy resolution of better than 600 eV full-width at half-maximum at 60 keV for a 2×2 mm² device without any charge-loss correction electronics. Large-area detectors with dimensions of 21×21 mm² are now available with an energy resolution of ∼2.8 keV. Long-term stability can be easily attained for relatively thin (<1 mm) detectors if they are cooled or operated under a high bias voltage.