title: High electron mobility in thin films formed via supersonic impact deposition of nanocrystals synthesized in nonthermal plasmas.
abstract: Thin films comprising semiconductor nanocrystals are emerging for applications in electronic and optoelectronic devices including light emitting diodes and solar cells. Achieving high charge carrier mobility in these films requires the identification and elimination of electronic traps on the nanocrystal surfaces. Herein, we show that in films comprising ZnO nanocrystals, an electron acceptor trap related to the presence of OH on the surface limits the conductivity. ZnO nanocrystal films were synthesized using a nonthermal plasma from diethyl zinc and oxygen and deposited by inertial impaction onto a variety of substrates. Surprisingly, coating the ZnO nanocrystals with a few nanometres of Al2O3 using atomic layer deposition decreased the film resistivity by seven orders of magnitude to values as low as 0.12 Ω cm. Electron mobility as high as 3 cm(2) V(-1) s(-1) was observed in films comprising annealed ZnO nanocrystals coated with Al2O3.
authors.affiliation: Department of Energy, Environmental and Chemical Engineering, Washington University, Saint Louis, Missouri 63130, USA.
authors.forename: Elijah
authors.initials: E
authors.lastname: Thimsen
authors.affiliation: Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA.
authors.forename: Melissa
authors.initials: M
authors.lastname: Johnson
authors.affiliation: Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Wagner
authors.affiliation: Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA.
authors.forename: K Andre
authors.initials: KA
authors.lastname: Mkhoyan
authors.affiliation: Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota 55455, USA.
authors.forename: Uwe R
authors.initials: UR
authors.lastname: Kortshagen
authors.affiliation: Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455, USA.
authors.forename: Eray S
authors.initials: ES
authors.lastname: Aydil