A single-step wet etch process is provided to isolate multijunction solar cells on semiconductor substrates, wherein the wet etch chemistry removes semiconductor materials nonselectively without a major difference in etch rate between different heteroepitaxial layers. The solar cells thus formed comprise multiple heterogeneous semiconductor layers epitaxially grown on the semiconductor substrate.

The process for manufacturing a semiconductor wafer includes steps for mounting a semiconductor work piece for exfoliation, energizing a microwave device for generating an energized beam sufficient for penetrating an outer surface layer of the semiconductor work piece, exfoliating the outer surface layer of the semiconductor work piece with the energized beam, and removing the exfoliated outer surface layer from the semiconductor work piece as the semiconductor wafer having a thickness less than 100 micrometers.

A method for producing a semiconductor element includes a step of forming a multiple quantum well in which a GaSb layer and an InAs layer are alternately stacked on a GaSb substrate by MOVPE, wherein, in the step of forming a multiple quantum well, an InSb film is formed on at least one of a lower-surface side and an upper-surface side of the InAs layer so as to be in contact with the InAs layer.

There is disclosed a method of preparing a photovoltaic device. In particular, the method comprises making thin-film GaAs solar cells integrated with low-cost, thermoformed, lightweight and wide acceptance angle mini-CPCs. The fabrication combines ND-ELO thin film cells that are cold-welded to a foil substrate, and subsequently attached to the CPCs in an adhesive-free transfer printing process. There is also disclosed an improved photovoltaic device made by the disclosed method. The improved photovoltaic device comprises a thin-film solar integrated with non-tracking mini-compound parabolic concentrators, wherein the plastic compound parabolic concentrator comprise two parabolas tilted at an angle equal to the acceptance angle of the compound parabolic concentrator.

After sequentially forming a first multilayer structure comprising a first set of semiconductor layers suitable for formation of a photodetector, an etch stop layer and a second multilayer structure comprising a second set of semiconductor layers suitable for formation of a light source over a substrate, the second multilayer structure is patterned to form a light source in a first region of the substrate. A first trench is then formed extending through the etch stop layer and the first multilayer structure to separate the first multilayer structure into a first part located underneath the light source and a second part that defines a photodetector located in a second region of the substrate. Next, an interlevel dielectric (ILD) layer is formed over the light source, the photodetector and the substrate. A second trench that defines a microfluidic channel is formed within the ILD layer and above the photodetector.

A method of forming an optoelectronic device and a silicon device on a single chip. The method may include; forming a stack of layers on a substrate in a first and second region, the stack of layers include a semiconductor layer, a first insulator layer, a waveguide, a second insulator layer, and a device base layer; forming the device on the device base layer in the second region; forming a device insulator layer on the device and on the device base layer in the second region; and forming the optoelectronic device in the first region, the optoelectronic device has a bottom cladding layer, an active region, and a top cladding layer, wherein the bottom cladding layer is on the semiconductor layer, the active region is on the bottom cladding layer, and the top cladding layer is on the active region.

A method for fabricating an upright photovoltaic cell comprises growing one or more epitaxial layers on a substrate, thereby forming a diffused active junction on the substrate and one more additional active junctions above the diffused active junction. The method further comprises selectively etching an areal region of the one or more epitaxial layers, thereby forming a mesa on the substrate and exposing a substrate-contact region parallel to the areal region at a base of the mesa. The method further comprises depositing contact material onto the substrate-contact region, to form the first contact, and concertedly onto a mesa-contact region of the mesa, to form the second contact.

Techniques for enhancing the absorption of photons in semiconductors with the use of microstructures are described. The microstructures, such as pillars and/or holes, effectively increase the effective absorption length resulting in a greater absorption of the photons. Using microstructures for absorption enhancement for silicon photodiodes and silicon avalanche photodiodes can result in bandwidths in excess of 10 Gb/s at photons with wavelengths of 850 nm, and with quantum efficiencies of approximately 90% or more.

Structures including crystalline material disposed in openings defined in a non-crystalline mask layer disposed over a substrate. A photovoltaic cell may be disposed above the crystalline material.

A photosensor device for reducing dark current is disclosed. The photosensor device includes a photon absorbing layer and two or more photosensor diffusions in said absorbing layer. The photosensor diffusions in the absorbing layer have edges of their diffusions separated in said absorbing layer by less than two minority carrier diffusion lengths. The photosensor device also includes in one embodiment one or more diffusion control junction diffusions in the absorbing layer and in proximity to the photosensor diffusions. In another embodiment the photosensor diffusions are selectively biased to operate as photosensor diodes or as diffusion impediments.