Systematic study of Ge1-xSnx absorption coefficient and refractive index for the device applications of Si-based optoelectronics
Systematic study of Ge1-xSnx absorption coefficient and refractive index for the device applications of Si-based optoelectronics
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DOI：
10.1063/1.4943652
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发表时间：
2016-03-14
影响因子：
3.2
通讯作者：
Yu, Shui-Qing
中科院分区：
文献类型：
--
作者：
Tran, Huong;Du, Wei;Yu, Shui-Qing
在1500 ~ 2500 nm波长范围内，用椭圆偏振光谱法测定了Ge1-xSnx合金（x为0% ~ 10%）在室温下的吸收系数和折射率。利用物理模型对所得数据进行拟合，得到了两个经验公式：(1)吸收系数。综合考虑了乌尔巴赫尾、间接和直接带隙跃迁的吸收；(2)折射率。提取与色散关系相关的Sellmeier系数。在这些公式中，Sn成分和应变百分比是输入参数，通过输入这些参数可以得到光谱吸收系数和光谱折射率。由于吸收系数是决定光电探测器工作波长范围、响应率和比探测率等性能的关键信息，而折射率对光电探测器增透涂层和波导层结构的设计非常有用，因此所建立的公式可以通过参数化表达来简化光电器件的设计过程。(C) 2016 AIP出版有限责任公司
The absorption coefficient and refractive index of Ge1-xSnx alloys (x from 0% to 10%) were characterized for the wavelength range from 1500 to 2500 nm via spectroscopic ellipsometry at room temperature. By applying physical models to fit the obtained data, two empirical formulae with extracted constants and coefficients were developed: (1) Absorption coefficient. The absorption regarding Urbach tail, indirect and direct bandgap transitions were comprehensively taken into account; (2) refractive index. The Sellmeier coefficients associated with dispersion relationship were extracted. In these formulae, the Sn composition and strain percentage were the input parameters, by inputting which the spectral absorption coefficient and spectral refractive index can be obtained. Since the absorption coefficient is key information to determine the performance of the photodetectors including operation wavelength range, responsivity, and specific detectivity, and the refractive index is very useful for the design of the anti-reflection coating for photodetectors and the layer structure for waveguides, the developed formulae could simplify the optoelectronic device design process due to their parameter-based expressions. (C) 2016 AIP Publishing LLC.