Noise in alloy-based resonant-tunneling structures

The noise properties of semiconductor alloy-based resonant-tunneling double-barrier quantum-well structures are calculated within a nonequilibrium Green's-function formulation. Alloy scattering is treated in the coherent-potential approximation including vertex corrections. Different noise characteristics are found depending on applied bias, scattering strength, and the transparency of the barriers. A characteristic frequency for the noise current power spectrum S({ω}) is given by the inverse response time.