Magnetoresistance of CdSe/CdS quantum dot films

Films of n-type CdSe/CdS colloidal quantum dots show positive and negative magnetoresistance (MR) with magnetic field lower than 0.4 T. The MR sign and magnitude vary with the occupancy of the lowest state, the temperature, and the electrical field. Low occupancy leads to +20% MR at 10 K, while high occupancy leads to similar to-5% MR. The MR reaches +35% in mixed samples of large and small dots. Intrinsic films are photoconductive and display positive MR. (C) 2009 American Institute of Physics. [doi:10.1063/1.3246157]