Scattering-assisted tunneling in double-barrier diodes: Scattering rates and valley current

We describe the valley current of double-barrier diodes as a scattering-assisted tunneling current. Scattering processes are included by using Fermi's golden rule between the unperturbed states of the tunneling structure, in a true three-dimensional calculation, without adjustable parameters. Intrinsic processes (optical and acoustic phonons, alloy disorder) are treated as well as the contribution of interface roughness. We apply it to several situations (geometry, doping, temperature, materials) and demonstrate that the calculated valley current agrees well with observation both with regard to structure in the valley current and peak-to-valley ratios.