A new fabrication technique of CdTe strip detectors for gamma-ray imaging and spectroscopy

Diode type CdTe strip detectors were fabricated in a new and simple technique for imaging and spectroscopy applications. On a high resistivity p-like single crystal CdTe water, n-type strips were formed by evaporating a thin indium layer on the crystal through a metallic shadow mask and then diffusing it inside the crystal by irradiating with an excimer laser. On the opposite side of the crystal a gold electrode was evaporated on the whole surface. The current-voltage characteristics of the detectors exhibited diode-like property with a low value of reverse bias leakage current from the individual strips. The spectral response from all strips was very good and uniform with typical energy resolutions of 2.5 keV and 3.6 keV FWHM at 59.5 keV peak of Am-241 and 122 keV peak of Co-57 radioisotopes, respectively for radiation detection tests performed at room temperature. Details about the detector fabrication and the spectral results that demonstrate the imaging and spectroscopy capabilities of these detectors are presented.