Evaluation method of radiative quantumn efficiency in amorphous semiconductor

用光热偏转光谱(PDS)和光声光谱(PAS)研究了薄膜固体的辐射量子效率。主要目的是建立氢化非晶硅、富勒烯薄膜、非晶氮化镓和非晶氧化硅的辐射量子效率的评价方法。(A)通过光致发光的光降解获得了辐射量子效率，在液氮温度下，氢化非晶硅的辐射量子效率约为30%。在表面，由于表面的局域态，RQE较低。用偏振光谱估算了表面和体相的局域态密度，其值分别为9.5×10~(-2)cm~(-2)和1.8×10~(-2)cm~(-2)。通过氧插层在富勒烯中的光致发光降解效应来估算RQE值。(C)TICS制备的氧化硅薄膜质量符合TFT的要求。测量了非晶态氮化镓的吸收系数谱。在非晶态材料中发现了很长的常温持续光电流。(D)利用PAS方法发展了RQEPAS方法。该方法改善了PPES方法由于光在PIRO装置金属电极上的反射和从金属电极透射光产生的噪声信号的误差。(E)发展了光热弯曲光谱技术，用于真空测量。现阶段的灵敏度为10^&lt；-3-10；-4&gt；其优点和缺点都已得到证明。

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.