Effect of Ge Incorporation on Bandgap and Photosensitivity of Amorphous SiGe Thin Films
Effect of Ge Incorporation on Bandgap and Photosensitivity of Amorphous SiGe Thin Films
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Ge掺入对非晶SiGe薄膜带隙和光敏性的影响
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
J. L. Harvey
中科院分区：
文献类型：
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作者：
G. Pethuraja;R. Welser;A. Sood;Changwoo Lee;N. Alexander;H. Efstathiadis;P. Haldar;J. L. Harvey
我们研究了用低成本、高生长速率沉积方法制备的非晶态SiGe薄膜的结构和光学性质。薄膜是通过电子束蒸发硅和锗的混合球团而形成的。通过改变硅、锗混合球团的重量比来改变薄膜的成分。薄膜为非晶态，成分均匀。富Ge薄膜处于张应力状态，而富Si薄膜处于压应力状态。随着Ge含量的增加(从22at.%增加到94at.%)，薄膜的光学带隙减小(从1.7 eV减小到0.9 eV)，薄膜的光敏性扩展到太阳光谱的红外波段。通过改变蒸发源混合物的加权比，可以很容易地调节a-SiGe薄膜的带隙和光学灵敏度。我们的研究证明a-SiGe薄膜是一种可调谐的吸收材料。这可用于光电探测器、光伏和微电子应用，以扩展光谱响应。
We investigated the structural and optical properties of amorphous-SiGe thin films synthesized via a low-cost, high-growth rate deposition method. Films were formed by e-beam evaporation of mixed pellets of Si and Ge. Film composition was varied by changing the weight ratio of Si and Ge pellets mixture. Films were amorphous with a composition uniform. Ge-rich films are in tensile stress, while Si-rich films are in compressive stress. As the Ge fraction increases (from 22 at.% to 94 at.%), the optical bandgap decreases (from 1.7 eV to 0.9 eV) and the photosensitivity of the films extends into IR band of solar spectrum. By changing the weighted ratio of the evaporation source mixture, the bandgap and optical sensitivity of a-SiGe films can be easily tuned. Our studies prove that a-SiGe films are a tunable absorber. This can be used for photo-detector, photovoltaic and microelectronic applications to extend the spectral response.