Thermoelectric devices are provided. In one embodiment, a thermoelectric device may include a glass wafer defined by conductive vias, a second wafer, and a plurality of metal film disposed between the glass wafer and the second wafer and against solid, conductive, integral, end surfaces of the conductive vias. A nanogap may be disposed between the metal film and the second wafer. The nanogap may have been created by applying a voltage extending between the conductive vias and the second wafer. Methods of forming the devices, along with methods of using the devices to transform heat energy to electricity, and for refrigeration, are also provided.