Study of radiation detectors based on semi-insulating GaAs and InP: Aspects of material and electrode technology

In this work, the most important aspects of semi-insulating (SI) GaAs and SI InP-based radiation detectors will be listed. Based on that, the material and technology requirements will be identified. Further, the status of development of X- and gamma-ray detectors based on the bulk SI GaAs and SI InP will be reviewed. The emphasis will be concentrated on the following important aspects: (1) basic material characteristics, (6) role of the electrodes (blocking contacts, ohmic contacts) in the overall performances of detectors. The fabrication technology and the performances of detectors and their application in the first quantum X-ray digital scanner recently developed will also be illustrated along with some conclusions about the material/application relations: (i) radiation detectors based on bulk SI GaAs may readily find applications in X-ray digital radiology imaging systems, whilst (ii) SI InP-based detectors are very promising but need further development to reach performances suitable for the application.