This invention includes quantum dot channel (QDC) Si FETs, which detect infrared radiation to serve as photodetectors. GeOx-cladded Ge quantum dots form the quantum dot channel. An assembly of cladded quantum dots, such as Ge and Si, with thin barrier layers (GeOx and SiOx) form a quantum dot superlattice (QDSL). A QDSL exhibits narrow energy widths of sub-bands (or mini-energy bands) with sub-bands separation ranging 0.2-0.5 eV. The energy separation depends on the barrier thickness (0.5-1 nm) and diameter of quantum dots (3-5 nm). Drain current magnitude in a QDSL layer or quantum dot channel depends on density of electrons in the QD inversion channel, which in turn depends on number of sub-bands participating in the conduction for a given drain voltage VD and gate voltage VG. Infrared photons with energy corresponding to the intra sub-band separation are absorbed as electrons in a lower sub-band make transition to the upper sub-band.

This invention includes quantum dot channel (QDC) Si FETs, which detect infrared radiation to serve as photodetectors. GeOx-cladded Ge quantum dots form the quantum dot channel. An assembly of cladded quantum dots, such as Ge and Si, with thin barrier layers (GeOx and SiOx) form a quantum dot superlattice (QDSL). A QDSL exhibits narrow energy widths of sub-bands (or mini-energy bands) with sub-bands separation ranging 0.2-0.5 eV. The energy separation depends on the barrier thickness (0.5-1 nm) and diameter of quantum dots (3-5 nm). Drain current magnitude in a QDSL layer or quantum dot channel depends on density of electrons in the QD inversion channel, which in turn depends on number of sub-bands participating in the conduction for a given drain voltage VD and gate voltage VG. Infrared photons with energy corresponding to the intra sub-band separation are absorbed as electrons in a lower sub-band make transition to the upper sub-band.

A transition metal chalcogenide flake manufactured by the molten salt-assisted thermal chemical vapor deposition method according to a preferred embodiment can be uniformly and evenly grown on a large-area substrate with a size of several to several hundred micrometers in scale, and a light-gated transistor using this as a light sensing layer can perform logical operations of AND, OR, and summation operations in response to light stimulation and enable a low-power synaptic operation response.

A transition metal chalcogenide flake manufactured by the molten salt-assisted thermal chemical vapor deposition method according to a preferred embodiment can be uniformly and evenly grown on a large-area substrate with a size of several to several hundred micrometers in scale, and a light-gated transistor using this as a light sensing layer can perform logical operations of AND, OR, and summation operations in response to light stimulation and enable a low-power synaptic operation response.

A graphene photodetector of the present invention includes a gate electrode for controlling a Fermi level of graphene, wherein the gate electrode is made of ZnO. By providing the graphene photodetector of the present invention, an ultra-high-speed photodetector having a 3 dB bandwidth exceeding 200 GHz can be realized.

A graphene photodetector of the present invention includes a gate electrode for controlling a Fermi level of graphene, wherein the gate electrode is made of ZnO. By providing the graphene photodetector of the present invention, an ultra-high-speed photodetector having a 3 dB bandwidth exceeding 200 GHz can be realized.

Provided are a light-receiving element which has more capability of detecting wavelengths than that of existing silicon light-receiving elements and a unit pixel of an image sensor by using it. The light-receiving element includes: a light-receiving unit which is floated or connected to external voltage and absorbs light; an oxide film which is formed to come in contact with a side of the light-receiving unit; a source and a drain which stand off the light-receiving unit with the oxide film in between and face each other; a channel which is formed between the source and the drain and forms an electric current between the source and the drain; and a wavelength expanding layer which is formed in at least one among the light-receiving unit, the oxide film and the channel and forms a plurality of local energy levels by using strained silicon.

Provided are a light-receiving element which has more capability of detecting wavelengths than that of existing silicon light-receiving elements and a unit pixel of an image sensor by using it. The light-receiving element includes: a light-receiving unit which is floated or connected to external voltage and absorbs light; an oxide film which is formed to come in contact with a side of the light-receiving unit; a source and a drain which stand off the light-receiving unit with the oxide film in between and face each other; a channel which is formed between the source and the drain and forms an electric current between the source and the drain; and a wavelength expanding layer which is formed in at least one among the light-receiving unit, the oxide film and the channel and forms a plurality of local energy levels by using strained silicon.

A germanium (Ge)-based infrared detector and an electronic device including the same are provided. The infrared detector according to an embodiment includes a Ge-based infrared absorption layer provided on a substrate; a first electrode layer provided on the infrared absorption layer; a second electrode layer provided on the infrared absorption layer and spaced apart from the first electrode layer in a first direction; and a first gate electrode layer provided between the first electrode layer and the second electrode layer in the first direction, the first gate electrode layer facing the infrared absorption layer and spaced apart from the infrared absorption layer in a second direction crossing the first direction.

A photodetector device to act as an artificial photonic synapse includes a substrate and a perovskite quantum dot-multiwall carbon nanotube (PQD-MWCNT) hybrid material. The PQD-MWCNT hybrid material channel is disposed on the substrate between a first electrode and a second electrode and forms a PQD-MWCNT channel. The PDQs comprise a methylammonium lead bromide material. A method of operating the photodetector device as an artificial photonic synapse includes applying a presynaptic signal as stimuli as one or more light pulses on the PQD-MWCNT channel between the first electrode and the second electrode. A current across the PQD-MWCNT channel is measured to represent a postsynaptic signal.