Evaluation method of radiative quantumn efficiency in amorphous semiconductor

利用光热偏转光谱（PDS）和光声光谱（PAS）研究了薄膜固体中的辐射量子效率。主要目的是建立氢化非晶态硅、富勒烯薄膜、非晶态氮化镓和非晶态氧化硅的辐射量子效率评价方法。(a)通过光致发光的光降解得到了辐射量子效率，在液氮温度下，氢化非晶硅的辐射量子效率约为30%。在表面，由于表面的局域化状态，RQE较低。用PDS估计了表面和体的局域态密度。取值分别为9.5x10^<12>cm^<-2>和1.8x10^<16>cm^<-2>。(b)找到了测量富勒烯薄膜的偏转介质。通过氧嵌入富勒烯的光致发光降解效应来估计RQE值。室温下为5-10%。(c) tic生产的氧化硅薄膜质量适用于TFT。测定了非晶态氮化镓的吸收系数谱。在非晶材料中发现了室温下非常长的持续光电流。(d)采用PAS法建立RQEPAS方法。该方法改善了PPES法在皮罗器件金属电极处反射光的误差和通过金属电极透射光的噪声信号的误差。(e)光热弯曲光谱是为了真空测量而开发的。现阶段的灵敏度为10^<-3>-10^<-4>。其优点和缺点已被证明。

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.