The present disclosure is directed to photovoltaic junctions and methods for producing the same. Embodiments of the disclosure may be incorporated in various devices for applications such as solar cells and light detectors and may demonstrate advantages compared to standard materials used for photovoltaic junctions such as silica. An example embodiment of the disclosure includes a photovoltaic junction, the junction including a light absorbing material, an electron acceptor for shuttling electrons, and a metallic contact. In general, embodiments of the disclosure as disclosed herein include photovoltaic junctions which provide absorption across one or more wavelengths in the range from about 200 nm to about 1000 nm, or from near IR (NIR) to ultra-violet (UV). Generally, these embodiments include a multi-layered light absorbing material that can be formed from quantum dots that are successively deposited on the surface of an electron acceptor (e.g., a semiconductor).

The present disclosure is directed to photovoltaic junctions and methods for producing the same. Embodiments of the disclosure may be incorporated in various devices for applications such as solar cells and light detectors and may demonstrate advantages compared to standard materials used for photovoltaic junctions such as silica. An example embodiment of the disclosure includes a photovoltaic junction, the junction including a light absorbing material, an electron acceptor for shuttling electrons, and a metallic contact. In general, embodiments of the disclosure as disclosed herein include photovoltaic junctions which provide absorption across one or more wavelengths in the range from about 200 nm to about 1000 nm, or from near IR (NIR) to ultra-violet (UV). Generally, these embodiments include a multi-layered light absorbing material that can be formed from quantum dots that are successively deposited on the surface of an electron acceptor (e.g., a semiconductor).

An open circuit voltage photodetector comprises a photovoltaic device including a photovoltaic junction, and a transistor. The photovoltaic device is connected to the gate terminal of the transistor to input an open circuit voltage of the photovoltaic device to the gate terminal. An array of such photodetectors and a readout integrated circuit forms an image sensor. In a photodetection method, an open circuit voltage is generated in a photovoltaic device in response to illumination by incident radiation, and the open circuit voltage is applied to a gate terminal of a transistor to modulate a channel current flowing in a channel of the transistor. A readout electronic circuit may be fabricated with an extra transistor, and a photovoltaic device disposed on the readout electronic circuit and electrically connected to apply an open circuit voltage of the photovoltaic device to a gate of the extra transistor.

An open circuit voltage photodetector comprises a photovoltaic device including a photovoltaic junction, and a transistor. The photovoltaic device is connected to the gate terminal of the transistor to input an open circuit voltage of the photovoltaic device to the gate terminal. An array of such photodetectors and a readout integrated circuit forms an image sensor. In a photodetection method, an open circuit voltage is generated in a photovoltaic device in response to illumination by incident radiation, and the open circuit voltage is applied to a gate terminal of a transistor to modulate a channel current flowing in a channel of the transistor. A readout electronic circuit may be fabricated with an extra transistor, and a photovoltaic device disposed on the readout electronic circuit and electrically connected to apply an open circuit voltage of the photovoltaic device to a gate of the extra transistor.

A photonic device that includes two electrodes and a two-dimensional (2D) material electrically connecting the two electrodes. The 2D material may be molybdenum ditelluride. Strain may be induced in the 2D material (e.g., by placing the 2D material on a waveguide) to reduce the band gap of the 2D material and increase the efficiency of the photodetector. The photonic device may be a photodetector with 2D material that absorbs light energy and converts it into a photocurrent in a circuit that includes the two electrodes. The photonic device may be an emitter with 2D material that emits light energy in response to an electric field across the two electrodes. The photonic device may be a modulator with 2D material that modulates a property of an optical signal (e.g., the amplitude or phase) by modulating the amount of strain induced in the 2D material.

An electromagnetic wave detector includes a semiconductor substrate, a first insulating film disposed on the semiconductor substrate and formed so as to expose a part of the semiconductor substrate, a first electrode disposed on the first insulating film, a two-dimensional material layer having a joint part forming a Schottky junction with the semiconductor substrate in a part of the semiconductor substrate, the two-dimensional material layer extending from the joint part to the first electrode over the first insulating film, a second electrode in contact with the semiconductor substrate, and a control electrode disposed at least partly around the joint part in plan view to form a Schottky junction with the semiconductor substrate.

An electromagnetic wave detector includes a semiconductor substrate, a first insulating film disposed on the semiconductor substrate and formed so as to expose a part of the semiconductor substrate, a first electrode disposed on the first insulating film, a two-dimensional material layer having a joint part forming a Schottky junction with the semiconductor substrate in a part of the semiconductor substrate, the two-dimensional material layer extending from the joint part to the first electrode over the first insulating film, a second electrode in contact with the semiconductor substrate, and a control electrode disposed at least partly around the joint part in plan view to form a Schottky junction with the semiconductor substrate.

The invention provides a laser rapid fabrication method for flexible gallium nitride (GaN) photodetector which comprises the following steps: (1) bonding a flexible substrate to a GaN epitaxial wafer; (2) adjusting the focal plane position of a light beam, and ensuring that the light beam is incident from the side of a GaN epitaxial wafer substrate; (3) enabling the light beam to perform scanning irradiation from the edge of a sample structure obtained in the step (1); (4) adjusting the process parameters, and scanning irradiation in the reverse direction along the path in the step (3); (5) remove the original rigid transparent substrate of the epitaxial wafer to obtain a Ga metal nanoparticle/GaN film/flexible substrate structure; and (6) preparing interdigital electrodes on the surfaces of the Ga metal nanoparticles obtained in the step (5).

The flexible GaN photodetector with Ga metal nanoparticle in-situ distribution detection surface is prepared in one step through laser technology, the process is simplified, meanwhile, the surface of the detector is induced to form the surface plasmon resonance effect, the light absorption and light response performance is greatly enhanced, and the flexible gallium nitride photodetector is suitable for industrial production.

An optical sensor structure is provided. The optical sensor structure includes a substrate, a light sensing unit, a peripheral wall, and a reflective layer. The substrate includes a plurality of metal pads. The light sensing unit is disposed on the substrate and electrically connected to the plurality of metal pads. The peripheral wall is disposed on the substrate, and the peripheral wall and the substrate define an accommodating space. The metal pads and the light sensing unit are positioned in the accommodating space. The reflective layer is disposed in the accommodating space and surrounds the light sensing unit.

An optical sensor structure is provided. The optical sensor structure includes a substrate, a light sensing unit, a peripheral wall, and a reflective layer. The substrate includes a plurality of metal pads. The light sensing unit is disposed on the substrate and electrically connected to the plurality of metal pads. The peripheral wall is disposed on the substrate, and the peripheral wall and the substrate define an accommodating space. The metal pads and the light sensing unit are positioned in the accommodating space. The reflective layer is disposed in the accommodating space and surrounds the light sensing unit.