a-Si∶H薄膜中SiyHx结构组态的原子模拟研究  

Atomic simulation of Si_yH_x structure configuration in a-Si:H thin films

作　　者：翟世铭 廖黄盛 周耐根 黄海宾 周浪 Zhai Shi-Ming;Liao Huang-Sheng;Zhou Nai-Gen;Huang Hai-Bin;Zhou Lang(School of Materials Science and Engineering,Institute of Photovoltaics,Nanchang University,Nanchang 330031,China)

机构地区：[1]南昌大学材料科学与工程学院,光伏研究院,南昌330031

出　　处：《物理学报》2020年第7期195-200,共6页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:51561022,51861023);江西省自然科学基金(批准号:20181BAB206013)资助的课题.

摘　　要：氢化非晶硅薄膜(a-Si∶H)中SiyHx结构组态对薄膜应用性能有重要影响,然而现有的分析测试手段难以对其进行深入细致的研究.本文运用分子动力学方法模拟分析了a-Si∶H/c-Si薄膜中SiyHx结构组态,以及衬底温度对其含量的影响;并进一步运用第一性原理方法计算了各SiyHx组态中的Si-H键能.结果发现a-Si∶H薄膜中SiyHx结构可以归纳为六种组态.三类为以化学键结合的SiHx组态,包括SiH,SiH2和SiH3;另外三类为以物理键结合的HSiy组态,包括HSi2(s),HSi2(l)和HSi3.键能结果反映出六种组态的稳定性由高到低的顺序为SiH>SiH2>SiH3>HSi2(s)>HSi2(l)>HSi3.HSiy组态中Si-H键能在太阳光中的可见光和红外线的能量范围内,阳光照射引起HSiy组态中的Si-H物理键断裂,是非晶硅薄膜电池产生S-W(Steabler-Wronski)效应的主要机理.另外,薄膜沉积过程中衬底温度的升高将导致各类SiyHx组态含量大幅降低.The hydrogenated amorphous silicon(a-Si:H)film is the core structure of hetero junction with intrinsic thin layer solar cell.Its quality determinates the photoelectric conversion efficiency of this solar cell directly.The configuration of SiyHx is an important structure characteristic of a-Si:H films,and it can influence on the quality of a-Si:H thin films and their application properties.However,it is difficult to study them in depth and detail by the existing analytical and testing methods.In this paper,the structure configuration of SiyHx in aSi:H/c-Si thin films and the effect of substrate temperature on its content have been simulated and analyzed by molecular dynamics method.A modified Tersoff potential developed by Murty was used to calculate the interatomic forces.The results showed that the SiyHx structure in a-Si:H thin films can be summarized into six configurations.Three traditional configurations,including SiH,SiH2 and SiH3,can be referred to as SiHx configurations.The other three nove configurations,including HSi2(s),HSi2(1)and HSi3,can be referred to as HSiy configurations.The main differences between the configurations of HSi2(1)and HSi2(s)are the longer Si-H bonds and bigger bond angle in HSi2(1)configuration than those in HSi2(s)configuration.All of the Si-H bonds in SiHx configurations are strong chemical bonds,while the Si-H bonds in HSiyconfigurations are weak physical bonds.The further calculations of the Si-H bond energies in six configurations have been carried out by the first principle method.According the bond energies results,we can deduce that the order of the stability of six configurations from high to low is SiH>SiH2>SiH3>HSi2(s)>HSi2(1)>HSi3.Comparing the Si-H bond energies of the six configurations with the solar energy,it is found that the Si-H bond energy in HSiy configuration is in the range of visible and infrared light in solar light.Si-H physical bonds are easy to fracture in HSiy configuration caused by solar light.This may be the main mechanism of producing Steabler-Wrons

关 键 词：SiyHx结构 键能 氢化非晶硅薄膜 分子动力学 

分 类 号：TN304.055[电子电信—物理电子学]