Nanocrystalline Si : H thin films grown at room temperature with plasma-enhanced chemical vapour deposition at a very high pressure
Nanocrystalline Si : H thin films grown at room temperature with plasma-enhanced chemical vapour deposition at a very high pressure
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DOI：
10.1088/0022-3727/45/33/335104
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发表时间：
2012-08
期刊：
影响因子：
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通讯作者：
L. Gao;N. Lu;L. Liao;A. Ji;Z. Cao
中科院分区：
文献类型：
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作者：
L. Gao;N. Lu;L. Liao;A. Ji;Z. Cao
使用等离子体增强化学气相沉积方法生长氢化纳米晶硅（nc-Si：H）薄膜，等离子体在高达30 mbar的气压下操作，即处于等离子体不稳定的边缘。在确定微晶尺寸和晶体体积分数中的加热效应可以被排除，因为在生长结束时最大衬底温度低于80 °C。在等离子体鞘层中发生微晶起始，并且仅当气体压力高于10 mbar时才出现Si纳米微晶。随着压力增加到30 mbar，纳米晶相的体积分数稳步增加，晶粒尺寸从0.78nm变化到0.45nm。沉积物的光学带隙在2.30 eV（在15 mbar下）和2.03 eV（在30 mbar下）之间变化，这可以用减少的氢含量和限制效应来解释。这项工作开辟了生长nc-Si：H薄膜的可能性，在接近室温的衬底上保持良好的控制微晶功能。
Hydrogenated nanocrystalline silicon (nc-Si : H) films were grown using the plasma-enhanced chemical vapour deposition method, with the plasma operated under a gas pressure of up to 30 mbar, i.e. on the verge of plasma instability. The heating effect in determining the crystallite size and crystalline volume fraction can be excluded as the maximum substrate temperature was below 80 °C at the end of growth. Crystallite initiation occurs in the plasma sheath, and Si nanocrystallites appear only when the gas pressure is above 10 mbar. With the pressure increasing to 30 mbar, the volume fraction of the nanocrystalline phase increases steadily, and the crystallite size changes from ∼7.8 to ∼4.5 nm. The optical bandgap of the deposits varies between 2.30 eV (at 15 mbar) and 2.03 eV (at 30 mbar), which can be explained in terms of the reduced hydrogen content and confinement effect. This work opens up the possibility of growing nc-Si : H films with well-controlled crystallite features on substrates held at near room temperature.