We made a characterisation of GaAs detectors with an epitaxial p-type layer deposited on the 200 μm semi-insulating substrate. The charge collection efficiency for 60-keV photons and 5.49 MeV alpha particle depends on the doping level of the p-layer. When completely depleted (reverse bias >200-300 V), the collected charge can be greater than 100%, implying the presence of some charge gain mechanism. At the same reverse bias and doping concentration, the collected charge depends also on the size of the contact pad. Moreover, the lower the p-doping, the lower the current density. The present findings confirm our previous work, obtaining gains up to 4:1
Evidence for charge gain mechanism in SI-GaAs detectors with epitaxial junction / Bertolucci, Ennio; A., Cola; Conti, Maurizio; A., De Luca; Mettivier, Giovanni; Russo, Paolo; F., Quaranta; L., Vasanelli. - 2:(1999), pp. 709-712. (Intervento presentato al convegno NUCLEAR SCIENCE SYMPOSIUM & MEDICAL IMAGING CONFERENCE tenutosi a Seattloe, WA, USA nel 24-30/10/1999) [10.1109/NSSMIC.1999.845766].
Evidence for charge gain mechanism in SI-GaAs detectors with epitaxial junction
BERTOLUCCI, ENNIO;CONTI, MAURIZIO;METTIVIER, GIOVANNI;RUSSO, PAOLO;
1999
Abstract
We made a characterisation of GaAs detectors with an epitaxial p-type layer deposited on the 200 μm semi-insulating substrate. The charge collection efficiency for 60-keV photons and 5.49 MeV alpha particle depends on the doping level of the p-layer. When completely depleted (reverse bias >200-300 V), the collected charge can be greater than 100%, implying the presence of some charge gain mechanism. At the same reverse bias and doping concentration, the collected charge depends also on the size of the contact pad. Moreover, the lower the p-doping, the lower the current density. The present findings confirm our previous work, obtaining gains up to 4:1I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
