Fan Zhiyuan, Geng Zhaoxin, Lv Xiaoqin, Su Yue, Yang Yuping, Liu Jian, Chen Hongda
State Key Laboratory of Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 10083, China.
College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Science, Beijing, 100049, China.
Sci Rep. 2017 Nov 1;7(1):14828. doi: 10.1038/s41598-017-13864-5.
The terahertz (THz) modulator, which will be applied in next-generation wireless communication, is a key device in a THz communication system. Current THz modulators based on traditional semiconductors and metamaterials have limited modulation depth or modulation range. Therefore, a THz modulator based on annealed tungsten disulfide (WS, p-type) and high-resistivity silicon (n-type) is demonstrated. Pumped by a laser, the modulator presents a laser power-dependent modulation effect. Ranging from 0.25 to 2 THz, the modulation depth reaches 99% when the pumping laser is 2.59 W/cm. The modulator works because the p-n heterojunction can separate and limit carriers to change the conductivity of the device, which results in a modulation of the THz wave. The wide band gap of WS can promote the separation and limitation of carriers to obtain a larger modulation depth, which provides a new direction for choosing new materials and new structures to fabricate a better THz modulator.
太赫兹（THz）调制器是太赫兹通信系统中的关键器件，将应用于下一代无线通信。目前基于传统半导体和超材料的太赫兹调制器调制深度或调制范围有限。因此，展示了一种基于退火二硫化钨（WS，p型）和高电阻率硅（n型）的太赫兹调制器。该调制器由激光泵浦，呈现出与激光功率相关的调制效应。在0.25至2太赫兹范围内，当泵浦激光为2.59 W/cm时，调制深度达到99%。该调制器之所以能工作，是因为p-n异质结可以分离并限制载流子，从而改变器件的电导率，进而实现对太赫兹波的调制。WS的宽带隙能够促进载流子的分离和限制，以获得更大的调制深度，这为选择新材料和新结构来制造更好的太赫兹调制器提供了新方向。
