Temperature dependence of hole mobility in methylated germanane field-effect transistor

Abstract

Methylated germanane, a layered material in which single-layer germanium is terminated by methyl groups, was utilized as a channel material of back-gate-type field-effect transistors (FETs). Titanium (Ti) and nickel (Ni) were used as source and drain electrodes of FETs, and the FET with the Ti electrode showed ambipolar characteristics, whereas that with the Ni electrode showed p-type characteristics. The maximum hole mobility at room temperature is 380 cm2V-1s-1, which is higher than those of typical transition metal dichalcogenides. The mobility changes with temperature T according to the T-3/2 law at temperatures ranging from 243 K to 343 K, suggesting that the major scattering factor of holes is acoustic phonons.