薄膜硅的变隙问题及隙态分布

用电子束蒸发的方法制备可变光学带隙薄膜硅材料, 给出了研究结果. 介绍了一种做透过率曲线切线确定薄膜光学带隙的简易方法, 给出了制备工艺和条件, 以及各种材料的隙态分布图. 实验发现, 材料的光学带隙宽度不但与量子尺度效应有关, 而且与缺陷形成的势垒高度和宽度以及有序短程(原子串)长度有关; 给出了常规硅材料的光学带隙与原子串长度的关系. 计算表明, 随着原子串长度的加大, 势阱中的电子液面升高, 载流子受缺陷势垒的散射减弱; 在原子串长度较低的情况下, 电子液面不总是随着原子串长度升高, 而是有较大的涨落, 形成锯齿状波动.计算还发现, 在势垒宽度与原子串长度之比不变的情况下, 电子液面还与势垒高度有关. 关键词： 薄膜硅 可变光学带隙 隙态分布 电子液面涨落

Variable gap and gap state distribution of film silicon

A method of preparing film silicon with variable optical gap is introduced, and the relevant results are given. An easy way to determine the film optical gap by transmittivity curve tangent is shown, and the preparation craftwork and conditions are given. The gap state distribution maps of various materials are presented. In experiment, it is found that the optical gap width of material is related not only to the quantum size effect, but also to the height and width of the barrier formed by lacuna, and to the length of short range order (atom cluster length) as well. A relationship between optical gap of silicon film and atom cluster length is given. Computations show that electron liquid level lifts in potential well with atom cluster length increasing, and the scattering of carrier is weakened by defect barrier. When the atom cluster length is shorter, the electron liquid level does not always lift with atom cluster length increasing, but fluctuates heavily and forms an indention wave. The computations also show that in the case of a constant ratio of the barrier width to the length of the atomic string, the electronic liquid level is also related to the barrier height.
Keywords： film silicon variable optical gap gap states distribution electronic liquid level fluctuating