Electronic transport of n-type CdSe quantum dot films: Effect of film treatment

Abstract

Solid films of CdSe colloidal quantum dots are conductive when reduced by electrochemistry. The dark conductivity and the photoconductivity of these $n$ -type CdSe nanocrystalline solids have been investigated as a function of film treatment. When the films are treated with NaOH, a carrier mobility of $\sim {10}^{-2}{\mathrm{cm}}^2∕\mathrm{V}\mathrm{s}$ and a charging/discharging time of $\sim 10\mathrm{ms}$ are obtained. Under an excitation intensity of $\sim 0.75\mathrm{mW}∕{\mathrm{cm}}^2$ , a significant photoconductivity of $\sim {10}^{-3}\mathrm{S}{\mathrm{cm}}^{-1}$ has been observed. The high mobility allowed demonstrating the operation of a field effect transistor.