锗硅量子阱结构带间吸收边研究

利用光电流谱的方法对锗硅量子阱结构的带间吸收边进行了研究.实验观察到了在不同的偏压和温度下,锗硅量子阱结构的带间吸收边谱线发生了有规律的变化.通过对锗硅量子阱材料的光电流谱的带间跃迁吸收边的拟合,得到了硅导带到锗价带的能带宽度分别为1.043 eV和1.050 eV.随着外加电场的增强,带边的吸收曲线向低能方向移动.通过理论计算得到了带间跃迁吸收边的漂移量与外加电场的关系,并与实验吻合较好.随着温度的降低,带间吸收边向高能方向偏移,对于这一现象给出了定性的解释,并通过拟合得到了禁带宽度随温度的变化率.

Band-to-Band Absorption Edges Study of Si/Ge Quantum Wells

The band-to-band absorption edges of Si/Ge quantum wells were characterized by photocurrent measurement.The regular change of absorption edge was observed in different bias voltage and temperature condition.By fitting of band-to-band absorption edges,the bandgap of Si conduction band to Ge valence band was acquired.With the increase of external electric field,absorption edge curves shifted to low energy direction.By theory calculation,the relationship between the shift of absorption and external electric field was obtained,and it was well agreement with experiment.With the decrease of temperature,absorption edge shifted toward high energy direction.The qualitative analysis of this phenomena was given,and the change rate of bandgap with temperature was acquired by fitting.