Amorphous germanium films were implanted to high boron levels, ∼1021/cm3peak concentrations. Before and after implantation the conductivity measurements fit the relation log&sgr;∼T−1/4and no evidence of intravalence absorption was observed indicating that the Fermi level was near the center of the band gap. Thermoelectric power measurements indicated that the samples were weaklyntype before implantation andptype after implantation. The position of the fundamental absorption edge shifted to lower energy upon implantation and to higher energies upon subsequent anneals. Implanted recrystallized films were stronglyptype, exhibited intravalence absorption, and had very low dc activation energies.