Properties of hydrogenated amorphous germanium nitrogen alloys prepared by reactive sputtering

Hydrogenated amorphous germanium-nitrogen alloys (a-GeN_x:H) were synthesized as a new group of amorphous semiconductors by rf(13.56 MHz) reactive sputtering of a Ge target in a gas mixture of Ar+N₂+H ₂ under a variety of deposition conditions such as gas ratio, rf-discharge power, and substrate temperature. Structural, optical, and electrical properties of those a-GeN_x:H alloys were systematically measured and are discussed in relation to their preparation conditions. The optical band gap E₀₄ of a-GeN_x:H alloys could be continuously controlled in the range from 1.1 eV to 3.3 eV primarily depending on the atomic N/Ge ratio in the film. The role of hydrogen and nitrogen in the optical and electrical properties of the material is also crucially demonstrated.