An improved design for maintaining separation between electrodes in tunneling, diode, thermionic, and other devices is disclosed. At least one electrode is made from flexible material. A magnetic field is present to combine with the current flowing in the flexible electrode and generate a force that counterbalances the electrostatic force between the electrodes. The balancing of forces allows the separation and parallelism between the electrodes to be maintained at a very small spacing without requiring the use of multiple control systems, actuators, or other manipulating means, or spacers. The shape of one or both electrodes is designed to maintain a constant separation over the entire overlapping area of the electrodes. The end result is an electronic device that maintains two closely spaced parallel electrodes in stable equilibrium with a uniform gap therebetween over a large area in a simple configuration for simplified manufacturability and use to convert heat to electricity or electricity to cooling.

Methods and apparatus for improved thermal isolation for thermoelectric devices are disclosed. In one embodiment, a thermoelectric device includes a first substrate having a first conductive pad, a second substrate having a second conductive pad, and a gap formed between the first and second conductive pads. At least one of the first and second substrates includes at least one opening positioned adjacent to an outer peripheral edge of the conductive pad. The opening may comprise a trench disposed partially or entirely around the outer peripheral edge of the conductive pad. In operation, the opening inhibits heat transfer between the first and second substrates.

A thermionic or thermotunneling gap diode device consisting of two silicon electrodes maintained at a desired distance from one another by means of spacers. These spacers are formed by oxidizing one electrode, protecting certain oxidized areas and removing the remainder of the oxidized layer. The protected oxidized areas remain as spacers. These spacers have the effect of maintaining the electrodes at a desired distance without the need for active elements, thus greatly reducing costs.

A diode device is disclosed, comprising a pair of electrodes separated by bellows. The corrugated walls of the bellows create a tortuous thermal pathway thereby reducing parasitic heat losses and increasing the device's efficiency. The bellows' also allow for a controlled environment to be sustained within the device. In a preferred embodiment the controlled environment is a vacuum. In one embodiment, a modified electrode for use in a diode device of the present invention is disclosed, in which indents are made on the surface of the electrode. In a further embodiment the bellows comprise shape memory alloys: previously deformed bellows are attached to the diode device and then grown to set the gap between the electrodes. In further embodiments the use of corrugation is applied to other parts of the diode device to elongate its thermal pathway and thereby increase its efficiency. For example, in one embodiment the outer rims of electrodes in a diode device are corrugated to increase the device's thermal pathway.