Fig. 4
From: Anisotropy of impact ionization in WSe2 field effect transistors
Temperature-dependent impact ionization for in-plane and out-of-plane transport. Drain current normalized by the saturation current for a in-plane transport and b out-of-plane transport at various temperature ranging from 80 to 300 K. c Critical electric fields of in-plane (black square) and out-of-plane (red square) transport as a function of the temperature. The critical electric field decreases with decreasing temperature; the decrease is very slight for in-plane transport. Conversely, for out-of-plane transport, the decrease in the critical electric field due to the temperature drop is relatively large because optical phonon scattering is dominant in this transport system