Modeling of Electron Transport in Thin Films With Quantum and Scattering Effects

With device dimensions shrinking to nanoscales, quantum effects such as confinement and tunneling become significant in electron transport. In addition, thermal transport in devices is directly coupled to charge transport even in highly scaled devices. While electron-phonon scattering usually helps restore thermodynamic equilibrium, shrinking device dimensions may not ensure enough scattering to restore equilibrium. The simultaneous consideration of scattering effects, which is usually described as particle behavior, and quantum effects, which are wave in nature, is extremely difficult and computationally intensive. Most device transport simulation models are not mature enough to couple quantum effects with strong scattering effects. In this paper, we couple quantum effects and scattering influences on electron transport using the non-equilibrium Green’s function formalism. Results indicate a 45 to 70 percent decrease in channel current for the case of near-elastic, phase-breaking, electron-phonon scattering. The single phonon energies ranged from 2meV to 20meV. The results illustrate the importance of including scattering effects with quantum transport. In addition, the NEGF model is used to assess the effect of temperature on device characteristics of thin film superlattices whose applications include thermoelectric cooling of electronic and optoelectronic systems. Results show the predicted Seebeck coefficient to be in good agreement with the measured values.