(color online) (a) – characteristics of HMG LTFETs with various dopant types and doping concentrations in the gap. The n-type dopants endow the transistor with a flat window. (b) – characteristics of HMG LTFETs with an n-type gap with increasing from 10¹⁹ cm to 10²⁰ cm . (c) Electron current density diagram in the lateral direction for HMG LTFETs with cm and 10²⁰ cm . (d) Calculated and extracted for HMG LTFETs with n-type gap as functions of .