Studies performed on the conduction and switching phenomena in films of certain amorphous chalcogenide semiconductors indicate that the electrical switching may be associated with a field-influenced dielectric phase transition. The normalized conduction found at voltages below switching displays an Ohmic and an exponential region, both associated with the same conduction process. This conduction is independent of frequency from dc to 100 kHz.T HE physics of amorphous semiconductors is incompletely understood. For this reason, it is an area of active theoretical and experimental study. 1 A very important phenomenon in many disordered semiconductors is the rapid electrical switching such as described by Ovshinsky. 2 This paper presents experimental evidence on the low-current conduction and on the switching phenomena in thin films of certain amorphous chalcogenide semiconducting materials. The main results found are: (1) The low-current conduction data can be normalized over a wide range of temperature and voltage. The resulting currents have an "Ohmic" region linear with voltage and exponentially varying nonlinear region both of which arise from the same conduction process. (2) A field-influenced phase transition, perhaps dielectric, is implicated in the switching process. The phase-transition temperature is equal to the glass-transition temperature within experimental error.A variety of experiments were performed mainly on commercial thin-film devices and to a lesser extent on thin films prepared in our laboratory. The commercial films 3 are prepared by a flash evaporation from premelted solid ingots of approximate composition by weight: 49% Te, 33% As, 6% Ge, 3% Si, and 9% Ga.The electronic band structures of SnS2 and SnSe 2 are calculated by using the empirical pseudopotential method. The potentials were obtained by scaling those used in other energy-band calculations. The symmetry properties of the crystals are treated in detail, and the optical constants are calculated. Comparison with experiment is also made.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.