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主要研究了THz量子级联激光器注入区结构的隧穿特性。通过量子力学方程设计出透射率最大的注入区结构。模拟结果表明,周期间势垒宽度为4.7 nm时,注入区的透射率最大。对于含有此注入区的QCL结构,模拟了在不同偏压下,电子波函数的空间分布和能级位置,进而模拟出该模型的隧穿点。计算结果表明,当每个周期两端的外加偏压为45 mV时达到THz工作点,同时满足周期间的电子隧穿条件。之后通过器件工艺,把外延片制作成实验样品。电流电压(I-V)测试曲线表明,在周期间偏压为50 mV时发生隧穿,这和理论计算的周期偏压为45 mV十分接近。
The tunneling characteristics of the THz quantum cascade laser injection region are mainly studied. Quantum mechanical equations were used to design the structure with the highest transmittance. The simulation results show that the transmissivity of the implanted region is the largest when the barrier width is 4.7 nm. For the QCL structure containing this implanted region, the spatial distribution and energy level position of the electron wave function under different bias voltages are simulated, and then the tunneling point of the model is simulated. The calculated results show that the THz operating point is reached when the applied bias voltage is 45 mV at each end of the cycle, and the electron tunneling condition is satisfied at the same time. After the process through the device, the epitaxial wafer made into experimental samples. The current-voltage (I-V) test curve shows that tunneling occurs at a bias voltage of 50 mV during the cycle, which is close to the theoretically calculated periodic bias of 45 mV.