纳米非晶氮化硅块体能态结构的紫外发射谱研究

Study on the Energy Band Structure of the Nanometer-Sized Amorphous Silicon Nitride Solids in terms of Ultraviolet Emission Spectra

用紫外荧光发射谱较系统地研究了纳米非晶氮化硅块体(粒径～10nm)的能态结构,观察到三个发射带,它们分别对应2.0、2.8和3.2eV.随热处理温度升高,峰高增大,低真空下1000℃退火又出现一个新峰,对应3.0eV.分析表明,2.0和3.2eV 发射峰与纳米非晶氮化硅高比例界面中 Si 悬键形成受主型和施主型局域态能级有关.能级2.0eV 和3.2eV 分别对应导带电子与受主型缺陷局域态空穴复合及施主型缺陷局域态电子及价带空穴复合,只有在高温(1000℃)退火才出现的3.0eV 发射带与O-Si-N 生成新的缺陷局域态有关.

A systematical study on the energy band structure was carried out by using ultravioletluminescent emission spectra for nanosize amorphous silicon nitride Solids.Three emissionbands corresponding respectively,to 2.0,2.8,and 3.2eV appear at the wavelength range from300nm to 670nm.With the increase of the heat treatment temperature,all peak heights rise.For the specimen,heat-treated at 1000℃ in vacuum of 1.33Pa,a new emission band occurs at410nm(3.0eV).From analysis,it is indicated that the Origin of the above three emission bandsis closely related to additive energy levels of the defect localized state,which are located in theenergy gap of nanosise silicon nitride solids,induced by Si dangling bonds in interfaces.Theelectron in the conductive band is trapped by the vacancy in the acceptor energy level,so thatthe emission band of 2.0eV appears and in case of trapping of the vacancy in the valent bandthe electron in the donor energy level leads the 3.2eV emission band to appear.The appearenceof the new emission band (3.0eV) is probably attributed to the formation of the new defectlocalized energy level associated with existing of O-Si-N bonds.