A solar cell includes polysilicon P-type and N-type doped regions on a backside of a substrate, such as a silicon wafer. A trench structure separates the P-type doped region from the N-type doped region. Each of the P-type and N-type doped regions may be formed over a thin dielectric layer. The trench structure may include a textured surface for increased solar radiation collection. Among other advantages, the resulting structure increases efficiency by providing isolation between adjacent P-type and N-type doped regions, thereby preventing recombination in a space charge region where the doped regions would have touched.

A method of fabricating a solar cell can include forming a dielectric region on a silicon substrate. The method can also include forming an emitter region over the dielectric region and forming a dopant region on a surface of the silicon substrate. In an embodiment, the method can include heating the silicon substrate at a temperature above 900 degrees Celsius to getter impurities to the emitter region and drive dopants from the dopant region to a portion of the silicon substrate.

The present disclosure provides methodologies for manufacturing high efficiency silicon photovoltaic devices using hydrogen passivation to improve performance. The processing techniques disclosed use tailored thermal processes, sometimes coupled with exposure to radiation to enable the use of cheaper silicon material to manufacture high efficiency photovoltaic devices.

Methods of fabricating solar cell emitter regions with differentiated P-type and N-type region architectures, and the resulting solar cells, are described herein. In an example, a solar cell includes an N-type semiconductor substrate having a light-receiving surface and a back surface. A plurality of N-type polycrystalline silicon regions is disposed on a first thin dielectric layer disposed on the back surface of the N-type semiconductor substrate. A plurality of P-type polycrystalline silicon regions is disposed on a second thin dielectric layer disposed in a corresponding one of a plurality of trenches interleaving the plurality of N-type polycrystalline silicon regions in the back surface of the N-type semiconductor substrate.

One embodiment can provide a photovoltaic roof tile. The photovoltaic roof tile can include a transparent front cover, a transparent back cover, and a plurality of polycrystalline-Si-based photovoltaic structures positioned between the front cover and the back cover. A respective polycrystalline-Si-based photovoltaic structure has a front surface facing the front cover and a back surface facing the back cover. The photovoltaic roof tile can further include a paint layer positioned on a back surface of the back cover facing away from the front cover. A color of the paint layer substantially matches a color of the front surface of the respective polycrystalline-Si-based photovoltaic structure.

A multi-level semiconductor device, the device including: a first level including integrated circuits; a second level including an optical waveguide, where the second level is disposed above the first level, where the first level includes crystalline silicon; and an oxide layer disposed between the first level and the second level, where the second level is bonded to the oxide layer, and where the bonded includes oxide to oxide bonds.

The luminance of a transmission mode X-ray scintillator diamond plate is dominated by induced defect centers having an excited state lifetime less than 10 msec, and in embodiments less than 1 msec, 100 usec, 10 used, 1 used, 100 nsec, or even 50 nsec, thereby providing enhanced X-ray luminance response and an X-ray flux dynamic range that is linear with X-ray flux on a log-log scale over at least three orders of magnitude. The diamond plate can be a single crystal having a dislocation density of less than 10.sup.4 per square centimeter, and having surfaces that are ion milled instead of mechanically polished. The defect centers can be SiV centers induced by silicon doping during CVD diamond formation, and/or NV0 centers formed by nitrogen doping followed by applying electron beam irradiation of the diamond plate and annealing.

Photodetectors using photonic crystals (PhCs) in polysilicon film that include an in-plane resonant defect. A biatomic photodetector includes an optical defect mode that is confined from all directions in the plane of the PhC by the photonic bandgap structure. The coupling of the resonance (or defect) mode to out-of-plane radiation can be adjusted by the design of the defect. Further, a guided-mode resonance (GMR) photodetector provides in-plane resonance through a second-order grating effect in the PhC. Absorption of an illumination field can be enhanced through this resonance.

Methods of fabricating conductive contacts for polycrystalline silicon features of solar cells, and the resulting solar cells, are described. In an example, a method of fabricating a solar cell includes providing a substrate having a polycrystalline silicon feature. The method also includes forming a conductive paste directly on the polycrystalline silicon feature. The method also includes firing the conductive paste at a temperature above approximately 700 degrees Celsius to form a conductive contact for the polycrystalline silicon feature. The method also includes, subsequent to firing the conductive paste, forming an anti-reflective coating (ARC) layer on the polycrystalline silicon feature and the conductive contact. The method also includes forming a conductive structure in an opening through the ARC layer and electrically contacting the conductive contact.

Method and structural embodiments are described which provide an integrated structure using polysilicon material having different optical properties in different regions of the structure.