Development of a homoepitaxial technology for fabrication of X- and gamma-ray detectors based on CdTe p-i-n diodes

The growth, processing and electrical characterization of n-type homo-epitaxial CdTe:I layers on detector-grade CdTe single crystal wafers is reported as a preliminary technological step towards the fabrication of CdTe-based p-i-n diode X-/gamma-ray detectors. n-type CdTe:I with resistivities around a few Omega.cm and electron concentrations in the mid 10(16) cm(-3) is demonstrated. Reactive ion etching of the n-type epilayer around the Al electrode proved necessary to improve the I-V characteristic of a Al/n-CdTe:I/i-CdTe/Pt device structure.