Self-oscillations in weakly coupled GaAs/AlGaAs superlattices at 77.3 K

We report 77.3 K self-oscillations in a 30-period weakly coupled GaAs/Al0.3Ga0.7As (28/10 nm) superlattice (SL). A study of frequency spectra of self-oscillations under external sinusoidal force in frequency-locked regime at different fixed voltages showed that current oscillations detected in the structureless regions of the I-V characteristic of weakly coupled SLs are forced oscillations. It was established that oscillations of free oscillator arising when the voltage is fixed at the first negative differential conductivity region at the beginning of the plateaulike region in the I-V characteristic are forcing oscillations. It was also shown that in order to describe the mechanism of the current oscillations in weakly coupled SLs, the model of the current oscillations in resonant tunneling diodes can be successfully applied.