A photo-sensitive device includes a uniform layer, a gradated buffer layer over the uniform layer, a silicon layer over the gradated buffer layer, a photo-sensitive light-sensing region in the uniform layer and the silicon layer, a device layer on the silicon layer, and a carrier wafer bonded to the device layer.

An improved heterostructure for an optoelectronic device is provided. The heterostructure includes an active region, an electron blocking layer, and a p-type contact layer. The heterostructure can include a p-type interlayer located between the electron blocking layer and the p-type contact layer. In an embodiment, the electron blocking layer can have a region of graded transition. The p-type interlayer can also include a region of graded transition.

An improved heterostructure for an optoelectronic device is provided. The heterostructure includes an active region, an electron blocking layer, and a p-type contact layer. The heterostructure can include a p-type interlayer located between the electron blocking layer and the p-type contact layer. In an embodiment, the electron blocking layer can have a region of graded transition. The p-type interlayer can also include a region of graded transition.

Structures for a photodetector or light absorber and methods of forming a structure for a photodetector or light absorber. The structure includes a pad, a waveguide core adjoined to the pad, and a light-absorbing layer on the pad. The waveguide core includes a first longitudinal axis, and the light-absorbing layer includes a second longitudinal axis and an end surface intersected by the second longitudinal axis. The end surface of the light-absorbing layer is positioned adjacent to the waveguide core. The first longitudinal axis of the first waveguide core is inclined relative to the second longitudinal axis of the light-absorbing layer and/or the end surface slanted relative to the second longitudinal axis.

A photoelectric conversion element for detecting the spot size of incident light, including a photoelectric conversion substrate provided with two main surfaces, and multiple first sensitivity sections and second sensitivity sections arranged in a prescribed direction. When sensitivity regions on the respective main surfaces of the multiple first sensitivity sections are defined as first sensitivity regions, and sensitivity regions that appear on the main surfaces of the second sensitivity sections are defined as second sensitivity regions, each of the first sensitivity regions receives at least a part of light incident on the main surfaces, and has a pattern in which, in accordance with enlargement of an irradiation region irradiated with incident light on the main surface, the proportion of the first sensitivity regions in the irradiation region with respect to the first sensitivity regions other than those in the irradiation region and the second sensitivity regions is decreased.

A photodetector has a substrate, a light input layer formed as a first semiconductor over the substrate, the first semiconductor being transparent to a wavelength being used, and a light absorption layer formed as a second semiconductor on the light input layer, the second semiconductor having a bandgap smaller than that of the first semiconductor. The light absorption layer has a first region doped with a first conductivity-type impurity, a second region doped with a second conductive-type impurity different from the first conductive-type impurity, and an undoped region between the first region and the second region. The first region, the undoped region and the second region are arranged in a direction parallel to the substrate. The light absorption layer has a region having an effective refractive index higher than the rest of the light absorption layer between the first region and the second region.

A photodetector has a substrate, a light input layer formed as a first semiconductor over the substrate, the first semiconductor being transparent to a wavelength being used, and a light absorption layer formed as a second semiconductor on the light input layer, the second semiconductor having a bandgap smaller than that of the first semiconductor. The light absorption layer has a first region doped with a first conductivity-type impurity, a second region doped with a second conductive-type impurity different from the first conductive-type impurity, and an undoped region between the first region and the second region. The first region, the undoped region and the second region are arranged in a direction parallel to the substrate. The light absorption layer has a region having an effective refractive index higher than the rest of the light absorption layer between the first region and the second region.

According to one embodiment, a light detector includes a plurality of elements, a plurality of insulating parts, and an intermediate part. The plurality of elements are arranged along a first direction and a second direction. The first direction and the second direction cross each other. Each of the plurality of elements includes a first semiconductor region and a second semiconductor region. The first semiconductor region is of a first conductivity type. The second semiconductor region is located around the first semiconductor region in a first plane. The first plane is along the first and second directions. The second semiconductor region is of a second conductivity type. The plurality of insulating parts are located respectively around the plurality of elements in the first plane. The intermediate part is located around the plurality of insulating parts in the first plane. The intermediate part includes a semiconductor.

According to one embodiment, a light detector includes a plurality of elements, a plurality of insulating parts, and an intermediate part. The plurality of elements are arranged along a first direction and a second direction. The first direction and the second direction cross each other. Each of the plurality of elements includes a first semiconductor region and a second semiconductor region. The first semiconductor region is of a first conductivity type. The second semiconductor region is located around the first semiconductor region in a first plane. The first plane is along the first and second directions. The second semiconductor region is of a second conductivity type. The plurality of insulating parts are located respectively around the plurality of elements in the first plane. The intermediate part is located around the plurality of insulating parts in the first plane. The intermediate part includes a semiconductor.

A semiconductor device includes a dielectric layer, a first trench located in the dielectric layer, a first semiconductor located in the first trench, a second semiconductor layer and an electrical connector. The dielectric layer has a first surface. The second semiconductor layer includes an active portion connecting the first semiconductor layer, and the electrical connector is located on the first surface and connects the second semiconductor layer.