Infrared Properties of 40–60 MeV Electron‐Irradiated Germanium

摘要

The infrared properties of germanium containing low oxygen concentration (≪1016 cm-3) and high oxygen concentration (≫1017 cm-3) have been studied after irradiation at T≤25°C by 40‐ to 60‐MeV electrons. One cold‐temperature irradiation at 125°K was also performed on a high oxygen concentration germanium sample. The germanium samples that were n type initially exhibit p‐type infrared properties in the 2‐ to 8‐μ wavelength range after being converted to p type by the irradiation. Germanium containing high oxygen concentration exhibits new vibrational bands in the 9‐ to 16‐μ wavelength range which are associated with oxygen‐defect complexes. No radiation‐induced bands from 9 to 16 μ are observed in oxygen‐free germanium. Detailed isochronal annealing experiments (up to ∼700°K) were performed on all samples. Strong evidence is given which shows that one of the oxygen vibrational bands induced in germanium (at 618 cm-1) appears to be a single oxygen atom plus a vacancy defect which corresponds to the comparable defect found in silicon, namely the silicon A center.