Epitaxial GaAs material shows a great potential in X-ray
spectroscopy and radiography applications due to its high
absorption efficiency and low defect density. Fabrication
of pixel radiation detectors from high-purtity epitaxial
GaAs has been developed further. The process is based on
mesa etching for pixellisation and sputtering for
metallization. The leakage currents of processed pad
detectors are below 10 nA/cm2 at a reverse bias of 100 V
and decrease exponentially with the temperature.
Measurement with transient current technique (TCT) shows
that electrons have a trapping time of 8 ns. Good
spectroscopic result were obtained from both a pad
detector and a hybridized Medipix GaAs detector.