Structural Properties of a-Ge1−xnx:H Alloys

Abstract

ABSTRACTAmorphous hydrogenated and unhydrogenated germanium-nitrogen alloys were prepared by rf glow discharge using a GeH4+NH3atmosphere and by rf sputtering using a Ge target with different gases (Ar, N2, NH3 , and mixtures). A difficulty in obtaining nonstoichiometric films was encountered for both methods. Films prepared by rf glow discharge tend to be either Gerich or close to stoichiometric composition, and films prepared by sputtering tend to have low nitrogen concentration. Thesamples prepared by glow discharge at 220°C do not contain the NH2 absorption band, which is usually present in filmsprepared by sputtering. The Urbach energy (determined by PDS), Tauc's gap, refractive index, dark conductivity and activation energy are also reported.