Embodiments of the present disclosure provide a photodetector, comprising a waveguide structure, a light limiting structure, and an absorption structure. The waveguide structure extends into the light limiting structure, and a first edge where a first side wall of the waveguide structure is located is tangent to a second edge where a second side wall of the light limiting structure is located. The waveguide structure is used for introducing incident light into the light limiting structure in a direction tangent to the first edge. The introduced light is limited in the light limiting structure for annular transmission by means of total reflection of a side wall of the light limiting structure, and the introduced light is coupled into the absorption structure by means of the light limiting structure. The absorption structure is located on the light limiting structure. The coupled light is limited in the absorption structure in the horizontal direction for annular transmission by means of total reflection of a side wall of the absorption structure, and the coupled light is converted into electrons and holes.

An imaging device may include single-photon avalanche diodes (SPADs). To improve the sensitivity and signal-to-noise ratio of the SPADs, light scattering structures may be formed in the semiconductor substrate to increase the path length of incident light through the semiconductor substrate. To mitigate crosstalk, multiple rings of isolation structures may be formed around the SPAD. An outer deep trench isolation structure may include a metal filler such as tungsten and may be configured to absorb light. The outer deep trench isolation structure therefore prevents crosstalk between adjacent SPADs. Additionally, one or more inner deep trench isolation structures may be included. The inner deep trench isolation structures may include a low-index filler to reflect light and keep incident light in the active area of the SPAD.

A short-wave infra-red, SWIR, radiation detection device comprises: a first metallic layer providing a first set of connections from a readout circuit to respective cells of a matrix, the metallic layer reflecting SWIR wavelength radiation. Each matrix cell comprises at least one stack of layers including: a first layer of doped semiconductor material formed on the first metallic layer; an at least partially microcrystalline semiconductor layer formed over the first doped layer; a second layer of semiconductor material formed on the microcrystalline semiconductor layer; at least one microcrystalline semiconductor layer; and in some embodiments a second metallic layer interfacing the microcrystalline semiconductor layer(s), the interface being responsive to incident SWIR radiation to generate carriers within the stack. The stack has a thickness

[00001]$T=\frac{}{2N}$

between reflective surfaces of the first and second metallic layers.

Disclosed are embodiments of a thin-film photovoltaic technology including a single-junction crystalline silicon solar cell with a photonic-plasmonic back-reflector structure for lightweight, flexible energy conversion applications. The back-reflector enables high absorption for long-wavelength and near-infrared photons via diffraction and light-concentration, implemented by periodic texturing of the bottom-contact layer by nanoimprint lithography. The thin-film crystalline silicon solar cell is implemented in a heterojunction design with amorphous silicon, where plasma enhanced chemical vapor deposition (PECVD) is used for all device layers, including a low-temperature crystalline silicon deposition step. Excimer laser crystallization is used to integrate crystalline and amorphous silicon within a monolithic process, where a thin layer of amorphous silicon is converted to a crystalline silicon seed layer prior to deposition of a crystalline silicon absorber layer via PECVD. The crystalline nature of the absorber layer and the back-reflector enable efficiencies higher than what is achievable in other thin-film silicon devices.

A semiconductor light receiving device (1) has a light receiving portion (6) with a light absorbing layer (4) on a first surface (2a) side of a semiconductor substrate (2) transparent to incident light in an infrared range for optical communications, a reflecting portion (11) in a region where light that was incident on the light receiving portion (6) and passed through the light absorbing layer (4) is reached on a second surface (2b) side opposite the first surface (2a) to reflect the light toward the second surface (2b), and end surfaces (2c, 2d) of the semiconductor substrate (2), where light reflected by the reflecting portion (11) and reflected by the second surface (2b) reaches, are formed as a rough surface having roughness with a height equal to or greater than the wavelength of the incident light.

An optical semiconductor device with cascade vias is disclosed. The semiconductor device a logic die having a core circuit area and a logic peripheral circuit area; a memory die positioned on the logic die and having a memory cell area and a memory peripheral area; a first inter-die via positioned in the memory peripheral area; a landing pad positioned on the first inter-die via; and a sensor die positioned on the memory die and including a sensor pixel area and a sensor peripheral area, a first intra-die via positioned in the sensor peripheral area. The first inter-die via and the first intra-die via are electrically coupled through the landing pad in a cascade manner.

An electromagnetic radiation detectors includes anti-reflective epitaxial structures incorporated into an epitaxial stack of the electromagnetic radiation detector. An anti-reflective structures as described herein are grown between (and thereby connect) two lattice-matched epitaxial layers that have different refractive indices. The anti-reflective structure reduces Fresnel reflections that would otherwise occur if the two epitaxial layers were directly connected.

In one embodiment described herein, a device includes optically reflective metal patches positioned within a dielectric substrate. A dielectric barrier layer separates the reflective metal patches and the dielectric substrate to prevent diffusion of the reflective metal into the dielectric substrate. An optically transparent dielectric spacer layer is deposited thereon, and an array of metal elements extend from the dielectric spacer layer. A dielectric coating is applied to the top wall and sidewalls of each metal element. A conductive barrier material is positioned between the base wall of each metal element and the dielectric spacer layer. A tunable dielectric material is positioned within the gaps between adjacent metal elements.

An electromagnetic radiation detector includes an InP substrate having a first surface opposite a second surface; a first InGaAs electromagnetic radiation absorber stacked on the first surface and configured to absorb a first set of electromagnetic radiation wavelengths; a set of one or more buffer layers stacked on the first InGaAs electromagnetic radiation absorber and configured to absorb at least some of the first set of electromagnetic radiation wavelengths; a second InGaAs electromagnetic radiation absorber stacked on the set of one or more buffer layers and configured to absorb a second set of electromagnetic radiation wavelengths; and an immersion condenser lens formed on the second surface and configured to direct electromagnetic radiation through the InP substrate and toward the first InGaAs electromagnetic radiation absorber and the second InGaAs electromagnetic radiation absorber.

A method of fabricating multijunction solar cell including an upper solar subcell and having an emitter of p conductivity type with a first band gap, and a base of n conductivity type with a second band gap greater than the first band gap; a lower solar subcell disposed below the upper solar subcell having an emitter of p conductivity type with a third band gap, and a base of n conductivity type with a fourth band gap greater than the third band gap; and an intermediate grading interlayer disposed between the upper and lower solar subcells and having a graded lattice constant that matches the upper first subcell on a first side and the second solar subcell on the second side opposite the first side, and having a fifth band gap that is greater than the second band gap of the upper solar subcell.