A semiconductor substrate contains a clathrate compound of the following General Formula (I). The semiconductor substrate includes a variable-composition layer which includes a pn junction and where composition of the clathrate compound varies along a thickness direction. A rate of change in y in the thickness direction of at least a portion of the variable-composition layer is 1×10.sup.−4/μm or more.
A.sub.xB.sub.yC.sub.46-y   (I) In General Formula (I), A represents at least one element selected from the group consisting of Ba, Na, Sr, and K, B represents at least one element selected from the group consisting of Au, Ag, Cu, Ni, and Al, and C represents at least one element selected from the group consisting of Si, Ge, and Sn, x is 7 to 9, and y is 3.5 to 6 or 11 to 17.

Various methods and devices for ultrasensitive infrared photodetection, infrared imaging, and other optoelectronic applications using the plasmon assisted thermoelectric effect in graphene are described. Infrared detection by the photo-thermoelectric uses the generation of a temperature gradient (ΔT) for the efficient collection of the generated hot-carriers. An asymmetric plasmon-induced hot-carrier Seebeck photodetection scheme at room temperature exhibits a remarkable responsivity along with an ultrafast response in the technologically relevant 8-12 μm band. This is achieved by engineering the asymmetric electronic environment of the generated hot carriers on chemical vapor deposition (CVD) grown large area nanopatterned monolayer graphene, which leads to a record ΔT across the device terminals thereby enhancing the photo-thermoelectric voltage beyond the theoretical limit for graphene. The results provide a strategy for uncooled, tunable, multispectral infrared detection.

A thermoelectric module includes a stack structure of a plurality of insulating layers, a plurality of thermoelectric elements formed with the insulating layer interposed therebetween and including a first-type semiconductor device, a second-type semiconductor device, a first electrode connected to the first-type semiconductor device, a second electrode connected to the second-type semiconductor device, and a connection electrode connecting the first-type and second-type semiconductor devices, and a conductive via penetrating through the insulating layer to connect thermoelectric elements adjacent to each other, among the plurality of thermoelectric elements.

A thermoelectric module includes a stack structure of a plurality of insulating layers, a plurality of thermoelectric elements formed with the insulating layer interposed therebetween and including a first-type semiconductor device, a second-type semiconductor device, a first electrode connected to the first-type semiconductor device, a second electrode connected to the second-type semiconductor device, and a connection electrode connecting the first-type and second-type semiconductor devices, and a conductive via penetrating through the insulating layer to connect thermoelectric elements adjacent to each other, among the plurality of thermoelectric elements.

A thermoelectric composite includes: a first layer including a thermoelectric semiconductor material; and a second layer including a conductive inorganic filler, wherein the first and second layers are stacked in layered form constituting a superlattice structure.

A thermoelectric composite includes: a first layer including a thermoelectric semiconductor material; and a second layer including a conductive inorganic filler, wherein the first and second layers are stacked in layered form constituting a superlattice structure.

Provided are a thermoelectric material having excellent thermoelectric characteristics at room temperature; a method for producing same; and a thermoelectric power generation element. In an embodiment of the present invention, the thermoelectric material contains an inorganic compound containing magnesium (Mg), silver (Ag), antimony (Sb) and copper (Cu), and is represented by the formula Mg.sub.1−aCu.sub.aAg.sub.bSb.sub.c, and the parameters a, b and c satisfy: 0<a≤0.1, 0.95≤b≤1.05 and 0.95≤c≤1.05. The inorganic compound may be an a phase of a half-Heusler structure and have the symmetry of the space group I-4c2.

A thermoelectric converter including a thermoelectric generator and a radiation source. The thermoelectric generator includes a hot source, a cold source, n-type material, and p-type material. The radiation source emits ionizing radiation that increases electrical conductivity. Also detailed is a method of using radiation to reach high efficiency with a thermoelectric converter that includes providing a thermoelectric generator and a radiation source, with the thermoelectric generator including a hot source, a cold source, n-type material, and p-type material, and emitting ionizing radiation with the radiation source to increase the electrical conductivity which strips electrons in the n-type material, the p-type material, or both the n-type material and p-type material from their nuclei with the electrons then free to move within the material.

A thermoelectric converter including a thermoelectric generator and a radiation source. The thermoelectric generator includes a hot source, a cold source, n-type material, and p-type material. The radiation source emits ionizing radiation that increases electrical conductivity. Also detailed is a method of using radiation to reach high efficiency with a thermoelectric converter that includes providing a thermoelectric generator and a radiation source, with the thermoelectric generator including a hot source, a cold source, n-type material, and p-type material, and emitting ionizing radiation with the radiation source to increase the electrical conductivity which strips electrons in the n-type material, the p-type material, or both the n-type material and p-type material from their nuclei with the electrons then free to move within the material.

A thermoelectric module comprising nanostructured SnO and SnO.sub.2, and electrodes arranged between two electrical insulating substrates is described. The nanostructured SnO may be in the form of nanosheets and acting as p-type pillars of the module. The nanostructured SnO.sub.2 may be in the form of nanospheres and acting as n-type pillars of the module. This thermoelectric module is evaluated on the voltage, current, and power of the electricity generated once subjected to a temperature gradient.