An integrated photodetector device includes a silicon region and an optically absorptive region formed within the silicon region. The optically absorptive region has a light incidence end and a distal end, where a light propagation direction extends from the light incidence end to the distal end. A first doped region is formed within the silicon region on a first side of the optically absorptive region. A second doped region is formed within the silicon region on a second side of the optically absorptive region. An optical waveguide is formed along a side of the optically absorptive region and spaced apart from the optically absorptive region. The optical waveguide is separated from the light incidence end of the optically absorptive region by a first distance. The optical waveguide is separated from the distal end of the optically absorptive region by a second distance that is less than the first distance.

Structures for a photonic chip that include a photodetector and methods of forming such structures. The structure comprises a photodetector including a pad, a first semiconductor layer on the pad, and a second semiconductor layer on the pad. The second semiconductor layer is laterally spaced from the first semiconductor layer. The structure further comprises a first waveguide core connected to the pad adjacent to the first semiconductor layer, and a second waveguide core connected to the pad adjacent to the second semiconductor layer.

Structures including a photodetector and methods of forming a structure including a photodetector. The structure comprises a photodetector including a pad having a side edge and a light-absorbing layer disposed on the pad. The structure further comprises a waveguide core including a tapered section positioned adjacent to the side edge of the pad and the light-absorbing layer. The tapered section has a width dimension that decreases with decreasing distance from the side edge of the pad.

Various embodiments of the present disclosure are directed towards an optoelectronic device. The device includes a substrate, and a germanium photodiode region extending into an upper surface of the substrate. The germanium photodiode region has a curved upper surface that extends past the upper surface of the substrate. A silicon cap overlies the curved upper surface of the germanium photodiode region. There is an absence of oxide between the curved upper surface of the germanium photodiode region and an upper surface of the silicon cap.

In some embodiments, the present disclosure relates to a semiconductor device, including a substrate including a first semiconductor material and a semiconductor layer extending into an upper surface of the substrate and including a second semiconductor material with a different band gap than the first semiconductor material. The semiconductor device also includes a passive cap including a first dielectric material and disposed along the upper surface of the substrate and on opposite sides of the semiconductor layer, and a photodetector in the semiconductor layer. The first dielectric material includes silicon nitride.

An integrated circuit includes a photodetector. The photodetector includes one or more dielectric structures positioned in a trench in a semiconductor substrate. The photodetector includes a photosensitive material positioned in the trench and covering the one or more dielectric structures. A dielectric layer covers the photosensitive material. The photosensitive material has an index of refraction that is greater than the indices of refraction of the dielectric structures and the dielectric layer.

A germanium single-crystal wafer comprises silicon with an atomic concentration of from 310.sup.14 atoms/cc to 1010.sup.18 atoms/cc, boron with an atomic concentration of from 110.sup.16 atoms/cc to 1010.sup.18 atoms/cc, and gallium with an atomic concentration of from 110.sup.16 atoms/cc to 1010.sup.19 atoms/cc. Further provided are a method for preparing the germanium single-crystal wafer, a method for preparing a germanium single-crystal ingot, and the use of the germanium single-crystal wafer for increasing the open-circuit voltage of a solar cell. The germanium single-crystal wafer has an improved electrical property in that it has a smaller difference in resistivity and carrier concentration.

A photodiode structure including a silicon substrate, an oxide layer on the silicon substrate, a silicon on insulator region on the oxide layer, a germanium absorption region, a silicon nitride waveguide, a cathode region, and an anode region is provided. The germanium absorption region is at least partially disposed in a recess of the silicon on insulator region. The germanium absorption region includes a top surface having a first width and a bottom surface having a second width, the first width being greater than the second width. The cathode region is formed at a first side of the germanium absorption region, and the anode region is formed at a second side of the germanium absorption region that is opposite the first side.

An optical communication receiver includes: a photodiode and signal processing circuitry coupled to the photodiode. The photodiode is configured to receive a modulated optical signal conveying data and convert the modulated optical signal to an electrical signal. The photodiode includes: a waveguide configured to receive the modulated optical signal; an absorption region above the waveguide; and a capacitor electrically coupled in series with the absorption region to reduce a capacitance of the photodiode as compared to a scenario in which the capacitor is omitted from the photodiode. The signal processing circuitry is configured to process the electrical signal to extract and output the data.

A photovoltaic cell includes a germanium-containing well embedded in a single crystalline silicon substrate and extending to a proximal horizontal surface of the single crystalline silicon substrate, wherein germanium-containing well includes germanium at an atomic percentage greater than 50%. A silicon-containing capping structure is located on a top surface of the germanium-containing well and includes silicon at an atomic percentage greater than 42%. The silicon-containing capping structure prevents oxidation of the germanium-containing well. A photovoltaic junction may be formed within, or across, the trench by implanting dopants of a first conductivity type and dopants of a second conductivity type.