Conley Benjamin R, Mosleh Aboozar, Ghetmiri Seyed Amir, Du Wei, Soref Richard A, Sun Greg, Margetis Joe, Tolle John, Naseem Hameed A, Yu Shui-Qing
Opt Express. 2014 Jun 30;22(13):15639-52. doi: 10.1364/OE.22.015639.
The GeSn direct gap material system, with Si complementary-metal-oxide semiconductor (CMOS) compatibility, presents a promising solution for direct incorporation of focal plane arrays with short wave infrared detection on Si. A temperature dependence study of GeSn photoconductors with 0.9, 3.2, and 7.0% Sn was conducted using both electrical and optical characterizations from 300 to 77 K. The GeSn layers were grown on Si substrates using a commercially available chemical vapor deposition reactor in a Si CMOS compatible process. Carrier activation energies due to ionization and trap states are extracted from the temperature dependent dark I-V characteristics. The temperature dependent spectral response of each photoconductor was measured, and a maximum long wavelength response to 2.1 μm was observed for the 7.0% Sn sample. The DC responsivity measured at 1.55 μm showed around two orders of magnitude improvement at reduced temperatures for all samples compared to room temperature measurements. The noise current and temperature dependent specific detectivity (D*) were also measured for each sample at 1.55 μm, and a maximum D* value of 1 × 10(9) cm·√Hz/W was observed at 77 K.
具有与硅互补金属氧化物半导体（CMOS）兼容性的锗锡直接带隙材料系统，为在硅上直接集成具有短波红外探测功能的焦平面阵列提供了一个有前景的解决方案。使用300至77K的电学和光学特性对含锡量分别为0.9%、3.2%和7.0%的锗锡光电导体进行了温度依赖性研究。锗锡层是在硅衬底上使用市售化学气相沉积反应器，通过与硅CMOS兼容的工艺生长的。从与温度相关的暗I-V特性中提取了由于电离和陷阱态引起的载流子激活能。测量了每个光电导体的温度相关光谱响应，在含锡量7.0%的样品中观察到最大长波长响应为2.1μm。与室温测量相比，在1.55μm处测量的直流响应度在低温下对所有样品都显示出约两个数量级的提高。还在1.55μm处测量了每个样品的噪声电流和与温度相关的比探测率（D*），在77K时观察到最大D*值为1×10⁹cm·√Hz/W。
