a-Si:H/SiO2多量子阱材料制备及其光学性能和微结构研究

摘要

利用等离子体增强化学气相沉积技术制备了a-Si:H/SiO2多量子阱结构材料.对a-Si:H/SiO2多量子阱样品分别进行了3种不同的热处理,其中样品经1100℃高温退火可获得尺寸可控的nc-Si:H:/SiO2量子点超晶格结构,其尺寸与非晶硅子层厚度相当.比较了a-Si:H:/SiO2多量子阱材料与相同制备工艺条件下a-Si:H材料的吸收系数,在紫外/可见短波段前者的吸收系数明显增大,光学吸收边蓝移,说明该材料具有明显的量子尺寸效应,验证了采用a-Si:H:/SiO2多量子阱结构来提高太阳能电池光电转换效率的可行性.另外,尺寸可控的nc-Si:H/SiO2量子点超晶格结构的形成,为纳米硅新结构太阳能电池的研究和制备奠定了基础.%a-Si: H/SiO2 multiple quantum wells ( QWs) are fabricated by plasma enhanced chemical vapor deposition (PECVD) and subsequent different thermal annealing. Among them the annealed sample under 1100 ℃ in vacuum can be transferred into nc-Si: H/SiO2 QWs, and the size of formed nc-Si: H is controllable and it matches the thickness of a-Si: H sublayer. The optical absorptivity of a-Si: H/SiO2 QWs is compared with that of a-Si: H under the same fabrication condition, the former is higher evidently in the UV/Visible spectrum with the absorption edge blue-shifted, which shows that a-Si: H/SiO2 QWs has an obvious quantum confinement effect. So it is feasible to use a-Si: H/SiO2 QWs to enhance the efficiency of silicon solar cells. In addition, the formation of nc-Si:H/SiO2 QWs with controllable size built the basis for new-type nanocrystalline silicon solar cells.