Quasi-hydrodynamic simulation of the features of electrical conduction in nanosized multilayer heavily doped heterostructures

Abstract

The electrical conduction in nanosized layered heterostructures in the presence of strong electric fields is studied via mathematical simulation based on the energy-balance equation and the quasi-hydrodynamic description of electron drift with allowance for the diffusion and thermal diffusion components of the current, the divergence of the thermal electron flow, and the temperature dependences of the mobility and energy-relaxation time. For the doping level in the range (5−1) × 10¹⁷ cm⁻³, the resulting I−V characteristics of heterostructures with a barrier height of 0.3 eV and equal widths of the narrow-and wide-band-gap components (50 nm) exhibit either a sharp peak of the differential conductivity or a bistability loop. A physical model that interprets the shape of the calculated characteristics on the basis of the cumulative effect of the electrostatic decrease in the height of heterobarriers and an increase in the electron temperature in the vicinity of the injecting heteroboundaries is proposed.