ALUMINUM IN HYDROGENATED AMORPHOUS-GERMANIUM

The effects of aluminium on the electro-optical properties of high qua lity sputtered hydrogenated amorphous germanium are reported. Two dist inct effects are found: at low concentrations, the aluminium atoms act as active p-type dopants making the Fermi level shift towards mid-gap compensating the intrinsically n-type material. At higher concentrati ons, a hydrogenated germanium-aluminium alloy is formed. The optical g ap shrinks and transport is probably dominated by holes.