Performance study of radiation detectors based on semi-insulating GaAs with P+ homo- and heterojunction blocking electrode

A preliminary study of technology and performance of radiation detectors based on bulk semi-insulating (SI) GaAs with P+ blocking electrodes is presented. Detectors with blocking electrode system formed either by P+(GaAs)/N–(SI GaAs) homojunction or P+(Al0.3Ga0.7As)/N–(SI GaAs) heterojunction are prepared. Room-temperature I–V characteristics, measurement and evaluation of pulse–height spectra using 241Am and 57Co radionuclide sources were performed for the characterization of the fabricated detectors. The aim of the study is to verify the possibility to improve the performances of SI GaAs radiation detectors based on the Schottky contact by using the more sophisticated P+–N junction technology. The obtained results and the possibility of future improvements of SI GaAs radiation detectors to be used in digital X-ray imaging are discussed.