High-purity, single-crystal cadmium telluride has been investigated from the viewpoint of its possible use for gamma-ray detection and spectroscopy. The width of its band gap makes the material an attractive possibility for room-temperature operation. At present, its performance is apparently limited by carrier trapping. Although surface barriers can be established on both p- and n-type materials, diffused junctions have not yet been obtained. Ohmic contacts have been formed on various materials under specific conditions. However, the general problem of establishing such contacts is still unsolved. In a limited number of crystals, magnesium or boron ions were found to drift within the crystal under the action of an electric field and thereby establish a compensated region. The surface barrier devices fabricated responded to both alpha particles and gamma rays. In some materials, pulses corresponding to the full particle energy were observed. The best resolution (for alpha particles) obtained as measured by the full width at half maximum was ∼25%. Noise levels even at elevated temperatures were generally below 20 keV. The main problems with presently available materials appear to be a lack of crystal uniformity and structural integrity.