A solar cell, a method for preparing the same and an electrical device are provided. The method for preparing the solar cell includes following steps: providing a substrate, which includes a first surface and a second surface opposite to the first surface; forming a protective material layer on the first surface, and removing part of the protective material layer on a preset first doped region to prepare a protective layer; performing a first doping process in the preset first doped region on the substrate to prepare a substrate including a first doped region. A width of the first doped region is in a range of 10 m to 35 m.

A photonic device is described in an embodiment. The photonic device comprising: a 2D material layer formed on a substrate; a source electrode and a drain electrode formed on the 2D material layer; and a plurality of nanoantennas formed on the 2D material layer between the source electrode and the drain electrode. Each of the plurality of nanoantennas having dimensions associated with a resonant wavelength of the photonic device and being configured to act as a non-centrosymmetric centre for providing anisotropy to generate a photocurrent in response to a polarized light incident on the photonic device, and the polarized light having a light wavelength near the resonant wavelength. The plurality of nanoantennas comprises one or more metal layers. The source electrode and the drain electrode are adapted to measure a photovoltage formed by the generated photocurrent, and a reduction in a magnitude of the photovoltage measured is used to detect a presence of an analyte having an absorption peak near the resonant wavelength of the photonic device. A photonic system comprising the photonic device and a method of spectroscopic sensing using the photonic system are also described.

A light-receiving device includes graphene including a light-receiving part; major electrodes electrically connected with the graphene, the major electrodes including a source electrode and a drain electrode, the light-receiving part being positioned between the source electrode and the drain electrode; a gate electrode electrically connected with the light-receiving part of the graphene via capacitive coupling; a circuit part electrically connected with the major electrode and the gate electrode; and an ionic substance contacting the light-receiving part of the graphene. The ionic substance is one of an anion having an acid dissociation constant of not less than 3 or a cation having an acid dissociation constant of not more than 11.

A pixel includes a first doped region of a first conductivity type and a second doped region of a second conductivity type. The first doped region includes first and second layers forming a heterojunction. A dopant concentration of the first layer is greater than a dopant concentration of the second layer. The first layer is made of a semiconductor material and the second layer includes quantum dots. The second doped region is in contact with the second layer, with the first layer being laterally surrounded by an insulated conductive wall that is biased to a negative voltage.

An optical semiconductor device includes: a first semiconductor layer having a first bandgap; and a second semiconductor layer having a second bandgap that is smaller than the first bandgap and formed on the first semiconductor layer. The first semiconductor layer includes a first conductive region with a first polarity, a second conductive region with a second polarity, and a first non-conductive region provided between the first conductive region and the second conductive region. The second semiconductor layer includes a third conductive region with the first polarity, and a second non-conductive region. The third conductive region is in contact with the first conductive region and the first non-conductive region. The second non-conductive region is in contact with at least one of the second conductive region and the first non-conductive region without being in contact with the first conductive region.

A photodetector includes a first semiconductor layer including germanium, a conductive layer that, in conjunction with the first semiconductor layer, forms a Schottky junction structure, and a tunneling barrier layer positioned between the first semiconductor layer and the conductive layer and configured to prevent dark current between the first semiconductor layer and the conductive layer.

A fabrication method of a solar cell, the method includes doping a silicon substrate having a first conductive type impurity with a second conductive type impurity, the second conductive type impurity being opposite to the first conductive type impurity, and thereby forming an emitter layer at a front surface part of the silicon substrate, forming an antireflection film on the emitter layer, forming a front electrode on the antireflection film, forming a rear electrode on a rear surface of the silicon substrate, and forming a back surface field layer at a rear surface part of the silicon substrate, the back surface field layer having a concentration of the first conductive type impurity that is higher than that of the silicon substrate, the back surface field layer having a different concentration of the second conductive type impurity from that of the emitter layer.

Various embodiments of a novel structure of a Ge/Si avalanche photodiode with an integrated heater, as well as a fabrication method thereof, are provided. In one aspect, a doped region is formed either on the top silicon layer or the silicon substrate layer to function as a resistor. When the environmental temperature decreases to a certain point, a temperature control loop will be automatically triggered and a proper bias is applied along the heater, thus the temperature of the junction region of a Ge/Si avalanche photodiode is kept within an optimized range to maintain high sensitivity of the avalanche photodiode and low bit-error rate level.

An apparatus comprising a plurality of solar cells that each comprise a nanowire titanium oxide core having graphene disposed thereon. By one approach this plurality of solar cells can comprise, at least in part, a titanium foil having the plurality of solar cells disposed thereon wherein at least a majority of the solar cells are aligned substantially parallel to one another and substantially perpendicular to the titanium foil. Such a plurality of solar cells can be disposed between a source of light and another modality of solar energy conversion such that both the solar cells and the another modality of solar energy conversion generate electricity using a same source of light.

Semi-conductor wafers with thin and thicker regions at controlled locations may be for Photovoltaics. The interior may be less than 180 microns or thinner, to 50 microns, with a thicker portion, at 180-250 microns. Thin wafers have higher efficiency. A thicker perimeter provides handling strength. Thicker stripes, landings and islands are for metallization coupling. Wafers may be made directly from a melt upon a template with regions of different heat extraction propensity arranged to correspond to locations of relative thicknesses. Interstitial oxygen is less than 610.sup.17 atoms/cc, preferably less than 210.sup.17, total oxygen less than 8.7510.sup.17 atoms/cc, preferably less than 5.2510.sup.17. Thicker regions form adjacent template regions having relatively higher heat extraction propensity; thinner regions adjacent regions with lesser extraction propensity. Thicker template regions have higher extraction propensity. Functional materials upon the template also have differing extraction propensities.