EAPSI:Investigating the Use of Graphene and Other 2D Materials for Use in Infrared Photodetectors

红外（IR）传感器通过吸收入射的IR辐射并将该能量转化为热量来工作。然后，来自吸收器的热量通过热电材料扩散，热电材料将热量转换为电能。然后，电信号可用于确定入射IR辐射的能量。然而，在吸收体和热电材料之间的接合处发生的损耗导致灵敏度和响应速度的降低，这降低了性能。通过使用石墨烯或其他二维（2D）材料，可以消除结。这是因为，尽管它们缺乏厚度，但这些材料具有良好的吸收性能，还可以将热量转化为电能，使它们成为改进的IR传感器的优秀候选者。了解最大化吸收和热电转换的参数对于创建更好的传感器至关重要。这项研究将与韩国水原成均馆大学（SKKU）著名的2D纳米材料专家Seong Chu Lim教授合作进行。ZnO和SbTe等热电材料广泛用于热应用，但由于带隙能量大，对入射的红外辐射是透明的。然而，石墨烯是良好的IR吸收剂。然而，基于石墨烯或其他2D材料的热电IR传感器将需要研究影响热电效应和IR响应度的参数。为了实现这一目标，研究人员将专注于提高对潜在物理现象的理解，以便实现传感器的系统改进。传感器的设计必须考虑传感器的器件物理和结构参数。如果可以实现将光电热效应转换为电输出的结构，则可以使用石墨烯作为吸收材料以恒定效率在宽光学范围内检测光。东亚和太平洋夏季研究所计划下的这个奖项支持美国研究生的夏季研究，由NSF和韩国国家研究基金会共同资助。

Infrared (IR) sensors operate by absorbing incoming IR radiation and transforming that energy into heat. This heat from the absorber is then diffused through a thermoelectric material that converts the heat into electricity. The electrical signal can then be used to determine the energy of the incoming IR radiation. However, losses occurring at the junction between the absorber and the thermoelectric material cause a reduction in sensitivity and response speed which degrades performance. By using graphene or other two dimensional (2D) materials, the junction can be eliminated. This is because, despite their lack of thickness, these materials have good absorption properties and can also transform heat into electricity, making them excellent candidates for improved IR sensors. Understanding of the parameters that maximize both the absorption and the thermoelectric conversion will be essential in creating better sensors. This research will be conducted in collaboration with Professor Seong Chu Lim, a noted expert on 2D nanomaterials, at Sungkyunkwan University (SKKU) in Suwon, South Korea.Thermoelectric materials such as ZnO and SbTe are widely used in thermal applications but are transparent to incoming IR radiation due to a large band gap energy. Graphene however is a good IR absorber. However, thermoelectric IR sensors based on graphene or other 2D materials will require investigation of the parameters that influence the thermoelectric effect and the IR responsivity. To accomplish this, the researcher will focus on improving the understanding of the underlying physical phenomena so that systematic improvements of the sensor can be realized. The design of the sensor must consider both device physics and structural parameters of the sensor. If a structure can be implemented that transduces the photothermoelectric effect into an electrical output, the detection of light over a wide optical range with a constant efficiency using graphene as the absorbing material is possible. This award under the East Asia and Pacific Summer Institutes program supports summer research by a U.S. graduate student and is jointly funded by NSF and the National Research Foundation of Korea.