Conduction in Charged PbSe Nanocrystal Films

Abstract

Conduction in thin films of PbSe nanocrystals doped by electrochemical gating has been studied. Charging the film, with either electrons or holes, increases the conductance by orders of magnitude. The electrons in the 1S_e state of nanocrystals in these films have a mobility as high as 5.0 × 10^-3 cm² V^-1 s^-1. Electrons in the 1P_e state were found to have a differential mobility up to 3−5 times greater than the electrons in the 1S_e state, and a mobility minima was found corresponding to the complete filling of the 1S_e state. The temperature and electric field dependence of conductance in the film, measured between 4.3 and 135 K, were both well described by a variable range hopping model.