Experimental investigation of ionized impurity scattering in double barrier resonant tunneling diodes

We investigate the asymmetry of I – V characteristics in a series of double barrier resonant tunneling structures (DBRTS) in which we intentionally insert a Si-delta doping sheet of varied concentration in one of the barrier. I – V characteristics are strongly affected by the presence of ionized impurities. We explain the peak current densities and the peak voltage variations within a coherent tunneling model while the potential profile is known from the solution of Poisson's equation. Our results suggest that the valley current originates from diffusion within the barrier between the accumulation layer and the quantum well (QW). The contribution of the exit barrier (between the QW and the depletion layer) to the valley current is less important.