LEC SI-GAAS DETECTORS FOR GAMMA-RAYS

Abstract

Detectors with a p-i-n structure based on Liquid Encapsulated Czochralski (LEC) grown Semi-Insulating (SI) GaAs have been fabricated. The current-voltage (I-V) characteristics and their response to gamma-rays have been studied. Measurements of the peak charge collection efficiency (cce) have been compared with a model assuming a uniform electric field. The comparison indicates that this field is not uniform. The peak cce at 500 V is found to be 52% and 82% in 400 mum and 200 mum thick detectors respectively. The resolution of the Co-57 full energy peak is between 10% and 13% at 400 V.