NOVELTY - A thermoelectric device is prepared by depositing a film of thermoelectric material on a substrate; locating one or more electrodes (20) within the thermoelectric film (22); partially oxidizing the film to form an oxide layer; and melting the oxide layer to form an electrical insulating and protective barrier on a top surface of the film. The melting step includes flash-heating the substrate to convert the oxide layer from a porous material into a dense glass material.    USE - The preparation method is used for preparing a thermoelectric device. The thermoelectric device is used in a refrigerator, a thermoelectric generator or a Peltier device (claimed).    ADVANTAGE - The preparation method generates practical thermoelectric devices from nanostructures that possess significantly larger ZT factors as compared to those of thermoelectrically active materials in bulk form. The thermoelectric device can be mass-produced at the ZT factor of greater than or equal to2.0. The thermoelectric device may be cost-effectively integrated into everyday heating and cooling products. The thermoelectric device provides a smaller footprint than the industry standard. The thermoelectric device is capable of being mass-produced at a lower cost than the current industry standard.    DETAILED DESCRIPTION - Preparation of a thermoelectric device includes:    (A) depositing a film of thermoelectric material on a substrate;    (B) locating one or more electrodes within the thermoelectric film;    (C) partially oxidizing the film to form an oxide layer; and    (D) melting the oxide layer to form an electrical insulating and protective barrier on a top surface of the film.    The melting step includes flash-heating the substrate to convert the oxide layer from a porous material into a dense glass material. The method steps are repeated to produce the thermoelectric device having thermoelectric film layers separated by electrical insulating barrier layers. A dimensionless thermoelectric figure of merit (ZT factor) of the resulting thermoelectric device is greater than or equal to0.5, preferably greater than or equal to2.5. The thermoelectric film is less than 300, preferably less than 100 nm in thickness. The thermoelectric film thickness is such that the ZT factor is enhanced through the effects of quantum confinement effects such that the ZT factor is higher than that of corresponding bulk material.    DESCRIPTION OF DRAWING(S) - The figure illustrates a top view of the thermoelectric film of the thermoelectric device.    Electrodes (20)    Thermoelectric film (22)