Fig. 2
From: Anisotropy of impact ionization in WSe2 field effect transistors
Impact ionization characteristics for different carrier transport directions. a Representative transfer curve of the lateral FET with a 240 nm WSe2 channel. b Output characteristics of the in-plane direction which shows impact ionization occurring above 1.4 V. c Representative transfer curve of the vertical FET employing 90 nm thick WSe2. d IDS–VDS characteristics of the out-of-plane direction exhibiting impact ionization occurring above 5.7 V. e Calculated multiplication factors for each direction as a function of the electric field. For impact ionization to occur in the out-of-plane direction, an electric field that is approximately ten times larger than that of the in-plane is required. (Inset: multiplication factors as a function of the electric field, normalized by the ECR.) f Distributions of the critical electric fields in tens of devices