Jeon Dohyeon, Kim Haesol, Gu Minji, Kim Taekyeong
Department of Physics and Memory and Catalyst Research Center, Hankuk University of Foreign Studies, 81 Oedae-ro, Yongin-si 17035, Republic of Korea.
Department of Physics and Memory and Catalyst Research Center, Hankuk University of Foreign Studies, 81 Oedae-ro, Yongin-si 17035, Republic of Korea.
Ultramicroscopy. 2022 Oct;240:113590. doi: 10.1016/j.ultramic.2022.113590. Epub 2022 Jul 22.
We report a local mapping photoresponse of WSe using a second-harmonic (2w) channel based on nondestructive electrostatic force microscopy (EFM). The 2w signals resulting from interaction between WSe and EFM tip are intrinsically related to the electrical conductivity of WSe. The photoresponse images and rise/decay time constants of WSe are obtained by local mapping 2w signals under illumination. We observe that the local photoresponse signals of WSe increase with the positive tip gate voltage while the WSe shows a p-type behavior in dark conditions We find that the reduced mobility of the photogenerated charge carriers resulting from the enhanced carrier scattering in the accumulation regime of WSe is responsible for the gate-dependent photoresponse behavior. Our results provide a deep understanding the intrinsic optoelectrical properties of WSe and contribute to the developments in the optoelectronic devices based on van der Waals layered materials.
我们报道了基于无损静电力显微镜（EFM）使用二次谐波（2ω）通道对WSe进行的局域映射光响应。WSe与EFM探针之间相互作用产生的2ω信号与WSe的电导率本质上相关。通过在光照下对局域映射的2ω信号进行测量，获得了WSe的光响应图像和上升/衰减时间常数。我们观察到，WSe的局域光响应信号随着正的探针栅极电压增加，而WSe在黑暗条件下表现出p型行为。我们发现，在WSe的积累区域中，由于载流子散射增强导致光生载流子迁移率降低，这是栅极依赖光响应行为的原因。我们的结果为深入理解WSe的本征光电特性提供了依据，并有助于基于范德华层状材料的光电器件的发展。
