State-Resolved Mobility of 1 cm²/(Vs) with HgSe Quantum Dot Films

HgSe colloidal quantum dot films are made by using a hybrid ligand exchange (HgSe/hybrid) in polar inks and compared with the solid-state ligand exchange using ethanedithiol (HgSe/EDT). In both systems, the conductance shows a peak at one-electron filling of the 1S_e state and a dip at 2 electrons before filling the 1P_e state. The HgSe/hybrid films show a ∼100-fold increased mobility, reaching up to ∼1 cm²/Vs for 7.5 nm diameter particles. While field effect transistor and Hall measurements give similar carrier density and mobility, the temperature dependence of the mobility is consistent with hopping transport.