Abstract
In this letter some properties of off-stoichiometric amorphous germanium-nitrogen compounds are presented. It is shown that the inclusion of nitrogen atoms in the Ge network produces important changes in the optical and electrical properties of the material. The samples were prepared by rf sputtering a Ge target in an argon plus nitrogen atmosphere. Optical transmission and dark conductivity versus temperature measurements are presented and discussed. The preparation conditions permitted the variation of the optical band gap in a continuous way between 0.9 and 2.7 eV. As expected for unhydrogenated samples, the dark conductivity measurements indicate a high density of states in the pseudogap, confirmed by an ill-defined activation energy. Preparation conditions that might improve the transport properties are indicated.