Patent ID: 8633373

Claim:
A sub-micron gap thermophotovoltaic structure for generating electrical power, comprising: an infrared radiation-emitting substrate having an external surface for receiving energy from a heat source and an opposing infrared radiation-emitting internal surface juxtaposed from a first surface of a radiation-transparent window substrate by a sub-micron gap; a radiation-transparent window substrate second surface opposing the radiation-transparent window substrate first surface, the radiation-transparent window substrate second surface affixed to a surface of a photovoltaic cell substrate by an adhesion layer having a capability of up-conversion of low-energy photons and high transmissivity in at infrared frequencies; the radiation-transparent window substrate having a refractive index that is equal to or greater than the refractive index of the infrared radiation-emitting substrate and the photovoltaic cell substrate as a means for improved collection and transmission of infrared energy from the infrared radiation-emitting internal surface of the infrared radiation-emitting substrate to the photovoltaic cell substrate; and the radiation-transparent window substrate being transparent to the radiation emitted by the infrared radiation-emitting substrate and selected from the group of materials consisting of single crystalline semi-insulating GaAs, single crystalline semi-insulating InP, float-zone Si, and lightly doped Si.