基于量子限制的受主带间跃迁太赫兹探测器的制备与测量

Preparation and Measurement of Terahertz Photodetectors Based on Quantum-confined Acceptor Transitions

使用分子束外延生长设备,在GaAs(100)衬底上生长了量子阱宽度为3 nm的GaAs/AlAs多量子阱样品,并在量子阱层中央进行了Be受主的δ-掺杂。根据量子限制受主从束缚态到非束缚态之间的跃迁,设计并制备了δ-掺杂Be受主GaAs/AlAs多量子阱太赫兹光探测器原型器件。在4.2 K温度下,分别对器件进行了太赫兹光电流谱和暗电流-电压曲线的测量。在6 V直流偏压下,空穴载流子沿量子阱层方向输运。当正入射激光频率为6.8 THz时,器件响应率为2×10-4V/W(2μA/W)。通过器件的暗电流-电压曲线计算了器件全散粒噪声电流,在4.2 K、6 V直流偏压下,全散粒噪声电流为5.03 fA·Hz-1/2。

3 nm well-width GaAs /AlAs multiple-quantum wells were grown by molecular beam epitaxy with Be acceptors δ-doped at quantum-well center on a semi-insulating GaAs(100) substrate.According to the transitions from bound to unbound states of quantum-confined acceptors,the terahertz prototype photodetector based Be acceptors-doped GaAs /AlAs multiple-quantum wells was designed and fabricated.The terahertz photocurrent spectrum and dark current-voltage characteristics of the device were measured at 4.2 K,respectively.Under a bias of 6 V and the normal incidence of a 6.8 THz laser,the hole carriers transport along quantum well layers,and the photodetector responsivity is 2 × 10- 4V /W(2 μA /W).According to the I-V curves measured at 4.2 K,the device full-shot noise current was calculated.It is 5.03 fA·Hz- 1 /2with a bias of 6 V.