Fig. 3
From: Anisotropy of impact ionization in WSe2 field effect transistors
Theoretical analysis of impact ionization. a Two-dimensional scattering rates for different phonon scatterings as a function of the carrier energy at T = 300 K. The acoustic phonon deformation potential is 2 eV and the nonpolar optical phonon deformation potential is 4 × 108 eV/cm. b Three-dimensional scattering rates for different phonon scatterings as a function of the carrier energy at T = 300 K in the Q conduction valley. The acoustic phonon deformation potential is 3 eV and the nonpolar optical phonon deformation potential is 5 × 108 eV/cm. c Monte Carlo simulated average carrier energy for in-plane transport as a function of the electric field at T = 100, 200, and 300 K. d Monte Carlo simulated average carrier energy for out-of-plane transport as a function of the electric field at T = 100, 200, and 300 K. The electric field required to reach E = 1.5∙Eg = 1.5 eV, the carrier energy for impact ionization, is exceptionally large for out-of-plane transport compared with in-plane