The Theoretic Modeling And Experimental Measurement Of The Thermo-optic Coefficient For Germanium-film

This assay used Kramers-Kronig formula to connect semiconductors’refractive index with their absorption coefficient, thus gave a study on refractive index through the study on absorption coefficient. This assay proposed a theoretical model of the temperature coefficient of a semiconductor’s refractive coefficient at its absorption limit (dn/dT) by dividing dn/dT into two parts:enhanced part (d△n1/dT)and un-enhanced part (d△n2/dT), and then study and calculate separately. This model shows a consistant trend of semiconudctor’s calorescence coefficient at study condition.In addition to theoretic work, this assay also proposed a new lab testing method for temperature coefficient of semiconductor’s refractive rate. In this new method, the analyzer can plate the semiconductor (germanium was used in our test) as a thin film on the end of the single-mode optical fiber and measure the refractive coefficient when the semiconductor is at different temperature, and calculate the temperature coefficient of the conductor’s refractive rate. The author did its analysis on an emulational experiment of semiconductor film and the result showed that the film thickness had a great effect on experimental sensitivity and also the theoretical calculation.To make sure the optic quality (refractive rate and absorption) of plated conductor film, in this case plate germanium film, is close to standard germanium, we made germanium films, using different plating methods, method one is magnetron sputtering plating, method two is vacuum evaporating plating. The semiconductor’s optical constant by two methods then was analyzes by high precision ellipsometery and testing result showed that method two provided a germanium film whose optical constant is closer to standard germanium’s.