Spontaneous quasi-periodic current self-oscillations in a weakly coupled GaAs/(Al,Ga)As superlattice at room temperature

Abstract

We have experimentally observed spontaneous quasi-periodic current self-oscillations at room temperature in a doped, weakly coupled GaAs/(Al,Ga)As superlattice (SL) with 50 periods, 7 nm well width, and 4 nm barrier width. The mole fraction of the aluminum in the barrier has been chosen to be 0.45 so that the direct barrier at the Γ point is as high as possible and thermal carrier leakage through the X valley is as small as possible. A spectral analysis of the current self-oscillations, which are observed under DC voltage bias alone, demonstrates that spontaneous quasi-periodic oscillation modes coexist with periodic ones.