自驱动拓扑半金属NiTe_(2)太赫兹探测器

Self-Driven Terahertz Detector Based on Topological Semimetal NiTe_(2)

太赫兹在高速通信、生物医学、无损检测、空间探测和安全防护等众多领域有广阔的应用前景,然而高灵敏室温太赫兹探测器是其亟待解决的难题之一.新兴拓扑材料特殊的光电子学性质为太赫兹探测开辟了新路径.基于第一性原理计算第Ⅱ类狄拉克半金属NiTe_(2)的能带结构及拓扑表面态,采用机械剥离法得到NiTe_(2)纳米片,通过集成电路工艺制备金属-NiTe_(2)-金属场效应晶体管,并测量其太赫兹光电流响应.结果表明,室温下NiTe_(2)响应度可达2.44 A/W,噪声等效功率约为14.96 pW/Hz^(1/2),在零偏压自驱动下,响应度仍有2.25 A/W,噪声等效功率下降到9.55 pW/Hz^(1/2),可与同类探测器媲美,且具有较大的线性度范围,在空气中也具有良好的稳定性.该器件良好的性能对进一步促进室温太赫兹探测器实际应用及集成具有重要意义.

Terahertz radiation has broad application prospects in many fields,including high-speed communication,biomedicine,nondestructive testing,space exploration,and security.However,the development of a highly sensitive room-temperature terahertz detector is an urgent issue that must be addressed.The special optoelectronic properties of emerging topological materials open up new paths for terahertz detection.In this study,the band structure and topological surface states of the type II Dirac semimetal NiTe_(2)were calculated based on first-principles calculations.NiTe_(2)nanosheets were obtained by mechanical exfoliation,and metal-NiTe_(2)-metal field effect transistors were fabricated using integratedcircuit processing technology.The photoelectric response of the device to terahertz radiation was measured.The results show that the NiTe_(2)-based terahertz detector has a high response rate of 2.44 A/W and a noise equivalent power of approximately 14.96 pW/Hz^(1/2).Particularly,even at a zero bias voltage,the response rate remains 2.25 A/W,and the noise equivalent power decreases to 9.55 pW/Hz^(1/2).These characteristics are better than those of similar terahertz detectors,and the device is stable in air and has excellent linearity within a certain range.These results are of great significance for further promoting the practical application and integration of room-temperature terahertz detectors.