基于D-S效应的太赫兹源研究

Research on Terahertz Source Based on the D-S Effect

基于Dyakonov-Shur效应（D-S效应）利用MOSFET可构建太赫兹源。研究表明MOSFET沟道内的1 m V信号在偏置电压的作用下产生波动并形成等离子波,其电学特性与谐振腔相似。当MOSFET外接5 V的偏置电压源时,输出频率为2.15 THz、峰值为2 m V的等离子信号。通过调节偏置电压（1-20 V）可以使输出信号在0.96-4.30 THz范围内调频。此外,MOSFET在5 V的偏置电压和5 A的偏置电流的共同作用下,沟道内产生的等离子波随时间的推移以指数形式放大。受器件限制和沟道夹断效应影响,该信号源的最大输出电压为20 V,电压增益最大可达到86 d B,最大输出功率为200 W。在器件允许范围内,偏置电压越大信号频率越高、偏置电流越大起振时间越短,且偏置电流引起的信号频偏小。

Based on the D-S effect,it is feasibility to build a terahertz source with the structure of MOSFET. The MOSFET biased by a voltage source act as a resonant cavity,and a small signal of 1 m V in the channel oscillates. When the bias voltage is fixed to 5 V,the frequency of plasma signal is 2. 15 THz and the peak value of voltage is 2 m V. Besides,the frequency can be tuned from 0. 96 to 4. 30 THz with the increasing bias voltage（ 1 - 20 V）. When the MOSFET is biased by a 5 V voltage source and a 5 A current source,the plasma signal is amplified in an exponential manner. Due to channel pinchedoff,the maximum voltage output is 20 V,the voltage gain up to 86 d B,and the maximum power output is 200 W. In the allowable range,the greater the bias voltage is,the higher the frequency will be; a great bias current will shorten the time of starting oscillation. Besides,the bias current cause a small frequency offset.