锗硅双层量子点的光电流特性

Photocurrent Study of Ge/Si Double Quantum Dots

在分子束外延 (MBE)系统上用自组织方式生长了硅基双层锗量子点结构 ,并对样品进行光电流谱的测试。通过调节不同外加偏压来改变量子点中的费米能级位置 ,量子点中载流子所处束缚能级将随之发生变化 ,所得到的光电流谱的峰位也将因此而改变。由光电流谱得到的实验结果与常规的光致发光谱的结果相吻合。与单层锗量子点结构相比 ,双层结构的样品在光电特性上有着明显不同 :光电流谱中 ,在 0 .767e V及 0 .869e V处出现了两个峰 ,分别对应于载流子在不同的量子点层中的吸收。

Room temperature infrared photocurrents of Ge/Si double quantum dots (QDs) are reported. The sample was grown in the Stranski Krastanov mode by molecular beam expitaxy. When the bias voltage is zero, the two peaks corresponding to two layers are located at 0.767 eV and 0.869 eV respectively. While increasing the bias voltage the peak locations make a shift. The photoluminescence measurement is used to confirm the existence of double quantum dots structure.