Evaluation method of radiative quantumn efficiency in amorphous semiconductor

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A radiative quantumn efficiency (RQE) in a thin film solid have been studied by using a photothermal deflection spectroscopy (PDS) and a photoacoustic spectroscopy (PAS). A main purpose is to develope the evaluation method for radiative quantumn efficiency of hydrogenated amorphous silicon, fullerene thin films, amorphous garium nitride and amorphous silicon oxide.(a) A radiative quantumn efficiency was obtained by the photo degradiation of photoluminescense, the value was about 30% in hydrogenated amorphous silicon at liquid nitrogen temperature. At the surface, the RQE was low because of the localized state at surface. Also the localized state density of a surface and bulk was estimated by PDS.The values are 9.5x10^<12>cm^<-2> and 1.8x10^<16>cm^<-2>, respectively.(b) The deflecting medium for a measurement of fullerene films has been found. And the RQE value was estimated by the photoluminescence degradiation effect by oxgen intercalation in the fullerene. The value was 5-10% at room temperature.(c) The film quality of silicon oxide produced by TICS is applicable to a TFT.The absorption coefficient spectrum of amorphous garium nitride was measured. The very long persistent photocurrent at room temperature was found in amorphous materials.(d) RQEPAS method was developed by using a PAS method. In this method, the errors of PPES method from light reflection at metal electrodes of piro device and the noise signal from transmitted light through metal electrodes was improved.(e) Photothermal bending spectroscopy was developed for the purpose of a measurement at vaccume. The sensitivity at present stage is 10^<-3>-10^<-4>. The merit and demerit has been demonstrated.