A semiconductor layered structure includes a base layer, a quantum well structure, and a contact layer. The base layer, the quantum well structure, and the contact layer are disposed so as to be stacked in this order. In the contact layer, a region including a first main surface that is a main surface on a quantum well structure side has a p-type impurity concentration lower than a p-type impurity concentration of a region including a second main surface that is a main surface opposite to the first main surface. A photodiode includes the semiconductor layered structure and an electrode formed on the semiconductor layered structure. A sensor includes the photodiode and a read-out circuit connected to the photodiode.

A superlattice absorber for a detector is provided. The superlattice absorber includes a plurality of material periods deposited successively. Each of the material periods includes a first layer of InAs, InGaAs, InAsSb or InGaAsSb; and a plurality of second layers of InGaAsSb. The second layers comprise at least two InGaAsSb layers with at least two different content combinations. The content of the second layers is different from that of the first layer.

A photovoltaic solar concentrator comprising a non-tracking lens adapted to reach the limits of Etendue conservation for acceptance of a direct and a diffuse solar insolation and to emit a focused light onto an upper surface of a luminescent solar concentrator (LSC). The LSC comprises a crystal with an un-doped semiconductor with high luminescence efficiency in the form of a waveguide that includes a top-hat multi-layer reflector to reflect photo-luminescence within an escape cone of the crystal. A mirror attached to the bottom surface. Mirrors attached to all edges of the crystal except for one of the edges. A solar cell mounted on an un-mirrored edge, or optically connected to the un-mirrored edge of the crystal by a second waveguide, to receive the photo-luminescence trapped within the waveguide.

A dual-band infrared detector is provided. The dual-band infrared detector includes a first absorption layer sensitive to radiation in only a short wavelength infrared spectral band, a plurality of barrier layers coupled to the first absorption layer, and a second absorption layer coupled to the plurality of barrier layers opposite the first absorption layer. The second absorption layer is sensitive to radiation in only a medium wavelength infrared spectral band, and the first and second absorption layers are formed from materials having a lattice parameter mismatch less than a predetermined threshold.

A method of forming an integrated circuit employs a plurality of layers formed on a substrate including i) bottom n-type ohmic contact layer, ii) p-type modulation doped quantum well structure (MDQWS) with a p-type charge sheet formed above the bottom n-type ohmic contact layer, iii) n-type MDQWS offset vertically above the p-type MDQWS, and iv) etch stop layer formed above the p-type MDQWS. P-type ions are implanted to define source/drain ion-implanted contact regions of a p-channel HFET which encompass the p-type MDQWS. An etch operation removes layers above the etch stop layer of iv) for the source/drain ion-implanted contact regions using an etchant that automatically stops at the etch stop layer of iv). Another etch operation removes remaining portions of the etch stop layer of iv) to form mesas that define an interface to the source/drain ion-implanted contact regions of the p-channel HFET. Source/Drain electrodes are on such mesas.

A photodetector comprising a photoabsorber, comprising a doped semiconductor, a contact layer comprising a doped semiconductor and a barrier layer comprising a charge carrier compensated semiconductor, the barrier layer compensated by doping impurities such that it exhibits a valence band energy level substantially equal to the valence band energy level of the photo absorbing layer and a conduction band energy level exhibiting a significant band gap in relation to the conduction band of the photo absorbing layer, the barrier layer disposed between the photoabsorber and contact layers. The relationship between the photo absorbing layer and contact layer valence and conduction band energies and the barrier layer conduction and valance band energies is selected to facilitate minority carrier current flow while inhibiting majority carrier current flow between the contact and photo absorbing layers.

The invention describes a device which enables MWIR photodetectors to operate at zero bias and deliver low dark current performance. The performance is achieved by incorporating a p-n junction in the barrier. The device consists of a p-type contact layer, a p-n junction in the compound barrier (CB) with graded composition and/or doping profiles, and an n-type absorber (p-CB-n) device.

A quantum cascade detector includes a semiconductor substrate; an active layer having a cascade structure; a lower cladding layer provided between the active layer and the substrate and having a lower refractive index than the active layer; a lower metal layer provided between the lower cladding layer and the substrate; an upper cladding layer provided on an opposite side to the substrate with respect to the active layer and having a lower refractive index than the active layer; and an upper metal layer provided on an opposite side to the active layer with respect to the upper cladding layer. A first end face being in a waveguide direction in a waveguide structure with the active layer, lower cladding layer, and upper cladding layer is an entrance surface for light to be detected.

A photovoltaic device and method include a substrate coupled to an emitter side structure on a first side of the substrate and a back side structure on a side opposite the first side of the substrate. The emitter side structure or the back side structure include layers alternating between wide band gap layers and narrow band gap layers to provide a multilayer contact with an effectively increased band offset with the substrate and/or an effectively higher doping level over a single material contact. An emitter contact is coupled to the emitter side structure on a light collecting end portion of the device. A back contact is coupled to the back side structure opposite the light collecting end portion.

A method for producing a semiconductor light receiving device includes the steps of growing a stacked semiconductor layer including a light-receiving layer having a super-lattice structure, the super-lattice structure including first and second semiconductor layers stacked alternately; forming a mesa structure by etching the stacked semiconductor layer, the mesa structure having a side surface exposed in an atmosphere; forming a deposited layer on the side surface of the mesa structure by supplying a silicon raw material, the deposited layer containing silicon generated from the silicon raw material; and, after the step of forming the deposited layer, forming a passivation film on the side surface of the mesa structure. The first semiconductor layer contains gallium as a constituent element. In the step of forming the deposited layer, the silicon raw material is supplied without supplying an oxygen raw material containing an oxygen element.