title: Size- and temperature-dependent charge transport in PbSe nanocrystal thin films.
abstract: We report the size- and temperature-dependence of electron transport in thin films of PbSe nanocrystals. Upon increasing temperature over the range 28-200 K, the electron transport underwent a transition in mechanism from Efros-Shklovskii-variable-range-hopping (ES-VRH) to nearest-neighbor-hopping (NNH). The transition occurred at higher temperatures for films with smaller particles. The electron localization length, estimated from the ES-VRH model, was comparable to the nanocrystal size and scaled systematically with nanocrystal diameter. The activation energy from the NNH regime was also size-dependent, which is attributed both to size-dependent Coulomb effects and the size-distribution of nanocrystals.
authors.affiliation: Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, Minnesota 55455, United States.
authors.forename: Moon Sung
authors.initials: MS
authors.lastname: Kang
authors.forename: Ayaskanta
authors.initials: A
authors.lastname: Sahu
authors.forename: David J
authors.initials: DJ
authors.lastname: Norris
authors.forename: C Daniel
authors.initials: CD
authors.lastname: Frisbie
mesh_terms: D003460:Crystallization; D004553:Electric Conductivity; D004583:Electrons; D007854:Lead / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D018036:Selenium Compounds / Q000737:chemistry*; D012666:Semiconductors; D013696:Temperature
chemical_list: D018036:Selenium Compounds; C088065:lead selenide; D007854:Lead