Charge Transport Properties of CdMnTe Radiation Detectors

Semiconductor gamma and X-ray detectors are finding increase use in medicine, industry, astronomy and national security. Conventional semiconductors consist mainly of germanium and silicon. Their use has however become marginalised in an increasing number of applications due to their physical limitations such as low detection efficiency and the need for bulky cryogenics. Detectors based on wide-bandgap high-Z compound semiconductors are logical choices to fulfill this technology need. A very recent and promising candidate is cadmium manganese telluride (CdMnTe). While previously used as Faraday rotors, solar cells and optical isolators, its application as a radiation detector was only first investigated in 1999 [1]. Its distinct advantages of good compositional homogeneity and a highly tunable band gap compared to CdZnTe and CdTe, which have been leading room temperature detector candidates for over three decades, have encouraged CdMnTe detector developments in recent years. Through a fruitful collaboration between Australian Nuclear Science and Technology Organisation and Brookhaven National Laboratory (USA) the performance of CdMnTe detectors are being investigated [2] and the detector properties are being improved.