石墨烯纳米带p-i-n结构太赫兹探测器的设计

Design of a p-i-n Structure Terahertz Detector Based on Graphene Nanoribbons

摘要:

研究了石墨烯纳米带横向p-i-n结构探测器对太赫兹波的响应特性, 基于载流子输运方程和泊松方程, 建立了考虑迁移、扩散、生成、复合等载流子运动的太赫兹探测器数学模型。根据该模型, 对石墨烯纳米带横向p-i-n结构的太赫兹波响应进行了仿真, 获得了反向栅压诱导生成的p-i-n二极管的能带图;进而探讨了纳米带宽度、i区长度及偏置电压对响应电流的影响, 分析表明石墨烯纳米带带隙随宽度增大而减小, 响应频率减小;i区长度与载流子寿命匹配时响应电流达到峰值;光电流随偏置电压的增大而增大, 并趋于饱和。

Abstract:

The response characteristics of terahertz (THz) detectors based on graphene nanoribbons(GNRs) with the lateral p-i-n structure were studied. With the consideration of carrier mobility, carrier diffusion, carrier generation, carrier recombination, the mathematical model of THz detectors was established based on carrier transport equation and Poisson equation. The terahertz response of the graphene nanoribbons terahertz detector was simulated according to this mathematical model. The band diagram of the p-i-n diode whose p-section and n-section are induced by the reverse gate voltage was obtained. Then the primary factors influencing on the response current, such as nanoribbons width, i-section length and bias voltage were discussed. It is indicated that the response current increases with the i-section length, reaches the maximum when the length of i-section and bias voltage are matched, and decreases when the i-section continues to increase. The photocurrent increases with the bias voltage, and will saturate gradually when the space charge region extends to the entire i-section region. The band gap and response frequence decrease with the increase of the nanoribbons’ width.