Fabrication of wide band gap semi-conductor materials based on amorphous carbon and development of new electronic devices

本研究的目的是建立一种基于非晶态碳的新型宽禁带半导体薄膜的制备方法。利用液态碳源，采用等离子体-化学气相沉积方法，在非晶态碳膜中掺入氮和硼原子。这些含氮和含硼薄膜分别具有n型和p型半导体电导。载流子密度可从3.24×10~(-3)~1.29×10~(-3)~1.29×10~(-3)。这些薄膜的光学带隙都很低(0。655-0。507 EV)。然后，将硅原子添加到N掺杂的非晶碳中，最高可达25个原子%。所得薄膜具有较高的光学带隙(约1.7 eV)。载流子密度和迁移率分别为4.789×1014 cm~(-3)和0。2981 cm^&lt；2；V^&lt；-1；S；-1&gt；在光电化学测量中，观察到了153μA cm~(-2)在氙气下的光电流。灯照度(11.8W m^&lt；-2&gt；)。这一数值与二氧化钛薄膜相近。量子产率为4.87%。结果表明，可以成功制备出入射光电流转换效率与二氧化钛相当的高性能半导体薄膜。

The objective of this study is to establish a method for fabricating novel wide gap semiconductor films based on amorphous carbon. Nitrogen and boron atoms could be incorporated in amorphous carbon films by plasma-CVD method using liquid carbon sources. These nitrogen-incorporated and boron-incorporated films showed n-type and p-type semi-conductivity, respectively. The carrier densities could be varied from 3. 24×10^<14> cm^<-3> to 1. 29×10^<19> cm^<-3>. Optical gaps of these films were quite low(0. 655-0. 507 eV). Then, Si atoms were added to N-doped amorphous carbon up to 25 atom%. Resulting films exhibited higher optical gap(ca. 1. 7 eV). The carrier density and mobility were 4. 789×1014 cm^<-3> and 0. 2981 cm^<2> V^<-1> s^<-1>, respectively. In photoelectrochemical measurement, the photocurrent of 153μA cm^<-2> was observed under Xenon? lamp illumination(11. 8 W m^<-2>). The value was close to that of TiO_2 thin films. The quantum yield was 4. 87%. It was concluded that high performance semi-conductive thin films of which incident photon-to-current conversion efficiency is equivalent to TiO_2 could be successfully synthesized.