The described embodiments of the present invention include a method for forming a radiation detector. A radiation absorption layer is formed on a substrate. A wider bandgap layer is formed on the radiation absorption layer. A passivation layer is formed on the wider bandgap layer. A doping layer is formed on the passivation layer. The doping layer is then patterned and dopant is driven from the patterned doping layer into the junction layer and the radiation absorption layer to form a doped region. The passivation layer is patterned to expose the doped region and an electrical contact to the doped region is formed.