23 results about "Free carrier absorption" patented technology

The present invention provides a manufacturing method for a TOPCon battery having a back SE structure. The method comprises forming a high-concentration thick-Poly structure in a metal region of an SE structure, and forming a low-concentration thin-Poly structure in a non-metal region. The present invention ensures both the thickness difference and the concentration difference of the structure manufactured by the present method; and the high-concentration thick-Poly metal region ensures contact performance of slurry, and the low-concentration thin-Poly structure in the non-metal region can reduce parasitic absorption and free carrier absorption, thus improving the short-circuit current.

The invention discloses a Sr-doped LaFeO3 high-emissivity coating and a preparation method thereof.The Sr-doped LaFeO3 high-emissivity coating is of a double-layer structure, and the structure of the coating sequentially comprises a metal substrate, a metal bonding layer and a high-emissivity layer from bottom to top; the metal substrate is made of a high-temperature Ni-based alloy, the metal bonding layer is a NiCrAlY alloy bonding layer or a CoNiCrAlY alloy bonding layer, and the high-emissivity layer is a La1-xSrxFeO3 layer (0 lt, x is smaller than or equal to 0.6) with different Sr doping amounts. LaFeO3 is selected as a matrix material, Sr < 2 + > is impurity ions with similar radiuses, impurity absorption and free carrier absorption in a crystal are increased through doping of Sr < 2 + >, the emissivity of the La1-xSrxFeO3 coating is improved, and the high-emissivity coating with the emissivity being 0.8 or above is prepared.

The application provides a TOPCon cell, which comprises a doped polysilicon layer; the doped polysilicon layer comprises a first doped polysilicon region and a second doped polysilicon alloy region; the first doped polysilicon region is selected from phosphorus-doped polysilicon; the second doped polysilicon alloy region is selected from phosphorus-doped polysilicon alloyed with at least one element selected from oxygen, carbon and nitrogen; the doping concentration of the first doped polysilicon region is not less than 1E20 cm ‑3 -3; the band gap of the second doped polysilicon alloy region is greater than that of the first doped polysilicon region, and the doping concentration of the second doped polysilicon alloy region is less than that of the first doped polysilicon region. The TOPCon cell structure provided by the application can ensure the thickness of the doped polysilicon in the metal contact region, avoid the destruction of the tunneling oxide layer in the slurry sintering process, reduce the recombination current and the contact resistance, and reduce the light parasitic absorption in the non-metal region, especially the free carrier absorption.

The present application relates to the field of optoelectronic technology, and in particular to a 980nm high-power semiconductor laser epitaxial wafer and a preparation method thereof. The epitaxial wafer comprises, from bottom to top along the growth direction, a GaAs substrate, a GaAs buffer layer, an N-side confinement layer, a first N-side graded-composition waveguide layer, a second N-side graded-composition waveguide layer, an N-side barrier layer, a quantum well, a P-side barrier layer, a P-side graded-composition waveguide layer, a P-side constant-composition waveguide layer, a P-side confinement layer and a GaAs ohmic contact layer. The present application widens the optical field to the N side through an asymmetric graded waveguide, reduces the cavity surface light power density and makes the heat evenly distributed; introduces tensile strain through a P-containing segmented strain waveguide, increases the band gap, reduces intrinsic absorption and free carrier absorption, enhances carrier confinement, suppresses non-radiative recombination and realizes strain compensation; optimizes the doping distribution to reduce heat generation. The COMD risk is reduced from the source, and the device reliability is improved.

The application provides a TOPCon cell, comprising: a single crystal silicon wafer; an inner expansion layer arranged on the back surface of the single crystal silicon wafer; a doped polysilicon layer arranged below the inner expansion layer; the doped polysilicon layer comprises: a first doped polysilicon region and a second doped polysilicon region, the doping concentration of the first doped polysilicon region is higher than that of the second doped polysilicon region; the inner layer comprises: a first inner expansion region and a second inner expansion region, the position of the first inner expansion region corresponds to the position of the first doped polysilicon region, and the junction depth of the first inner expansion region is greater than that of the second inner expansion region. The TOPCon cell provided by the application has a specific structure, which can ensure the thickness and concentration of the doped polysilicon in the metal contact area, avoid the destruction of the tunneling oxide layer in the slurry sintering process, reduce the recombination current and the contact resistance, and at the same time, reduce the light parasitic absorption of the non-metal area, especially the free carrier absorption.

The utility model provides a semiconductor laser which is provided with an epitaxial layer. The epitaxial layer comprises a p-type waveguide layer, a p-type cladding and an ohmic contact layer. And a grating layer is arranged in the p-type cladding. Wherein the doping concentration of the material of the grating layer is smaller than or equal to the doping concentration of the material of the p-type cladding, and the doping concentration of the p-type cladding is larger than the doping concentration of the p-type waveguide layer. According to the semiconductor laser, the doping concentration of the grating layer is reduced, the absorption level of free carriers is reduced, free carrier absorption is reduced, the band gap difference between the grating layer and the p-type cladding is utilized, the loss type coupling grating is formed, and single longitudinal mode lasing of the semiconductor laser is achieved.

The invention relates to a method for measuring electrical properties of a semiconductor quantum dot material based on free carrier absorption. Comprising the following steps that pumping laser and continuous detection laser are sequentially emitted to the same position of a semiconductor sample to be detected, the power of the pumping laser is changed, the concentration of free carriers is subjected to nonlinear change, the nonlinear characteristic of the free carriers is closely related to the characteristics of excitons and carriers in quantum dots, and the concentration of the free carriers is detected. Transmitting light signal data at different powers are collected through a photoelectric detector, and the obtained data are recorded and processed to obtain electrical characteristic parameters of the detected semiconductor sample. The method is not influenced by the response time or bandwidth limitation of the photoelectric detector, the data processing is simple, and the measurement precision is high; the measuring device is simpler, and the equipment cost is low; the method is wide in application range, can be used for measuring quantum dot materials with deep energy level traps, and is particularly suitable for measuring quantum dot materials with more shallow energy level traps.

A semiconductor laser. The semiconductor laser sequentially comprises, from bottom to top, a substrate (100), a lower confinement layer (101), a lower waveguide layer (102), an active layer (103), an upper waveguide layer (104), and an upper confinement layer (105), wherein the lower confinement layer (101) is composed of at least one material of AlInGaN, AlInN, AlGaN, InN, AlN, InGaN, and GaN, the thickness of the lower confinement layer (101) is x, and x is greater than or equal to 10 angstroms and less than or equal to 90,000 angstroms; and the lower confinement layer (101) comprises a first lower confinement layer (101a), a second lower confinement layer (101b), and a third lower confinement layer (101c). The lower confinement layer (101) is used to form an electron storage structure and a stress regulation structure, thereby regulating carrier distribution and stress distribution in the active layer (103), reducing threshold current of the laser, and improving the slope efficiency. Moreover, heat generated by non-radiative recombination loss and free carrier absorption loss is reduced, heat accumulation in the active layer (103) is reduced, thermal conductivity and heat dissipation performance are improved, aging and light attenuation of the laser are alleviated, and focal spot resolution of the laser is improved.

The present invention belongs to the technical field of solar cells, and provides a method for testing free carrier absorption loss and a battery sample. The method includes: preparing a battery sample with a specific structure, the battery sample including a first region with no doping in the local areas of the front surface and the rear surface, a second region with a first heavily doped layer in the local area of the front surface and no doping in the local area of the rear surface, and a third region with no doping in the local area of the front surface and a second heavily doped layer in the local area of the rear surface; testing the external quantum efficiency of the first region, the second region and the third region in the near-infrared band; obtaining the integral current density values of the first region, the second region and the third region according to the external quantum efficiency of the first region, the second region and the third region and the AM1.5G spectrum; obtaining the free carrier absorption loss according to the integral current density values of the first region, the second region and the third region. This method is simpler to test, takes less time and has a lower cost, and can quickly and accurately achieve the quantitative detection of free carrier absorption loss.

The invention provides a TOPCon solar cell, a preparation method thereof and a photovoltaic module. The TOPCon solar cell comprises a hole selective emitter layer arranged on a first main surface of an n-type silicon wafer and an electron selective passivation contact structure arranged on a second main surface of the silicon wafer, wherein the passivation contact structure comprises a tunneling oxide layer and an n + polycrystalline silicon layer; the first main surface and / or the second main surface are / is provided with a graphical opening area, and the graphical opening area comprises a passive film covering the surface of the silicon wafer and an anti-reflection film covering the surface of the passive film; and forming an undoped pyramid structure on the surface of the silicon wafer in the patterned opening region. According to the TOPCon solar cell, the absorption loss of infrared free carriers can be reduced, the film layer stress and the film explosion risk are relieved, and the process flexibility and adjustability are high.

The invention discloses a method for regulating and controlling the nonlinearity of an optical waveguide, and belongs to the technical field of optoelectronic devices, and the method comprises the steps: constructing a waveguide structure with sub-wavelength scale periodicity, and enabling the periodicity size to meet lambda < lt >; lambda / (2n), lambda is the period length, lambda is the incident light wavelength, and n is the effective refractive index of the medium; the sub-wavelength grating waveguide is integrated on an SOI platform or a heterogeneous integrated substrate; by adjusting the unit size, the spacing, the duty ratio and the geometrical shape of the sub-wavelength structure, the effective refractive index of the waveguide is regulated and controlled, the effective mode area is increased, the electric field intensity in the unit area is reduced, and two-photon absorption TPA and free carrier absorption FCA are inhibited; and the nonlinear threshold power of the waveguide is improved by using the equivalent dielectric characteristic of the sub-wavelength structure. The non-linear absorption effect can be effectively reduced, and the power threshold value of the waveguide is remarkably improved.

The present invention discloses an Sr-doped LaFeO3 high-emissivity coating and a preparation method thereof. The Sr-doped LaFeO3 high-emissivity coating is a double-layer structure, wherein the coating structure comprises a metal substrate, a metal bonding layer and a high-emissivity layer from bottom to top; the metal substrate is a high-temperature Ni-based alloy, the metal bonding layer is a NiCrAlY alloy bonding layer or a CoNiCrAlY alloy bonding layer, and the high-emissivity layer is LaFeO3 with different Sr doping amounts. 1‑x Sr x FeO3 layer (0< x ≤0.6). The present invention selects LaFeO3 as the matrix material, Sr 2+ are impurity ions with similar radii, Sr 2+ The doping of La increases the impurity absorption and free carrier absorption in the crystal, making La 1‑x Sr x The emissivity of the FeO3 coating was improved, and a high emissivity coating with an emissivity above 0.8 was prepared.

The application provides a solar cell and a preparation method thereof. The solar cell comprises a silicon substrate having a first surface and a second surface arranged oppositely, the first surface comprising electrode regions and non-electrode regions arranged alternately; a first tunneling oxide layer, a first doped polysilicon layer, a second tunneling oxide layer and a second doped polysilicon layer arranged sequentially on the first surface and / or the second surface; wherein the first doped polysilicon layer is doped with a first dopant and a second dopant, and the second doped polysilicon layer is doped with the first dopant, and the doping concentration of the first dopant in the second doped polysilicon layer is greater than the doping concentration of the first dopant in the first doped polysilicon layer. The first doped polysilicon layer in the solar cell can achieve excellent passivation and significantly reduced free carrier absorption, and the second doped polysilicon layer can achieve rapid transport of carriers and excellent field passivation, which is helpful to improve the open-circuit voltage and the fill factor.

The invention relates to the technical field of photoelectric devices, in particular to a near-infrared 2 [mu] m ITO / Si mixed PIN heterojunction electro-optical modulator structure which comprises a Si substrate, a SiO2 supporting layer and a PIN heterojunction, a transverse asymmetric PIN heterojunction design is adopted, carriers are injected from the upper side and the lower side of a silicon waveguide core area through an N-type heavily-doped ITO area and a P-type heavily-doped Si area respectively, and the silicon waveguide core area and the P-type heavily-doped Si area are combined to form the near-infrared 2 [mu] m ITO / Si mixed PIN heterojunction electro-optical modulator structure. By means of the carrier injection efficiency enhanced by the ITO / Si heterojunction, remarkable refractive index regulation and control can be achieved under low driving voltage, and the modulation efficiency is greatly improved; meanwhile, the core area of the silicon waveguide is accurately aligned with the heavily doped areas on the two sides, it is ensured that an optical mode field is fully covered by an electric field, optical loss caused by free carrier absorption is effectively restrained, and therefore low insertion loss is maintained while the high extinction ratio is obtained. The collaborative design enables the electro-optical modulator to realize the unification of high efficiency, low loss and high extinction ratio in a 2-micron wave band.

This invention provides a TOPCon battery structure with two polycrystalline silicon layers and its fabrication method, relating to the field of battery processing technology. The TOPCon battery structure includes a monocrystalline silicon wafer, with a diffusion layer, a passivation layer, a front antireflection layer, and a front metal electrode sequentially disposed on the front side of the monocrystalline silicon wafer, and a tunneling layer, a doped polycrystalline silicon layer, a back antireflection layer, and a back metal electrode sequentially disposed on the back side of the monocrystalline silicon wafer. The doped polycrystalline silicon layer includes a first doped polycrystalline silicon layer located on the back side and a second doped polycrystalline silicon layer located between the back metal electrode and the first doped polycrystalline silicon layer, wherein the doping concentration of the second doped polycrystalline silicon layer is greater than that of the first doped polycrystalline silicon layer. This invention overcomes the shortcomings of existing technologies, ensuring the thickness of the doped polycrystalline silicon in the metal contact area, preventing damage to the tunneling oxide layer during sintering, and reducing recombination current and contact resistance; simultaneously, it reduces photoparasitic absorption in the non-metallic region, especially reducing free carrier absorption.

The invention provides a TOPCon solar cell with a localized passivation contact structure, a manufacturing method of the TOPCon solar cell and a cell module. The TOPCon solar cell with the localized passivation contact structure comprises a cell silicon wafer; the polycrystalline silicon stack layer is arranged on the back surface of the battery silicon wafer; the dielectric layer is arranged between the polycrystalline silicon stack layer and the battery silicon wafer; the groove extends along the thickness direction of the TOPCon solar cell and penetrates through the polycrystalline silicon stack layer and the dielectric layer; the polycrystalline silicon stack layer is divided into at least one localization area, and the localization area comprises a first area and a second area surrounding the first area; in the TOPCon solar cell, the groove is located in the first region and / or the second region. According to the TOPCon solar cell, the absorption loss of infrared free carriers can be reduced, the stability of a passivation interface is improved, the film stress and the film explosion risk are relieved, and the local carrier collection capacity is enhanced.

This application provides a set of test samples, methods, and applications for testing the free carrier absorption of polycrystalline silicon layers, belonging to the field of solar cell technology. The method for testing the free carrier absorption of polycrystalline silicon layers includes the following steps: preparing a set of test samples, comprising a test sample and a control sample; measuring the optical absorptivity A1 of the test sample and the optical absorptivity A2 of the control sample in a preset wavelength band; integrating A1 and A2 in the preset wavelength band to obtain the current density J1 of the test sample and the current density J2 of the control sample, and then calculating the current density J3 of the polycrystalline silicon layer using Formula 1; Formula 1 is as follows: J3 = J1 - J2. This method can solve the problems of cumbersome sample preparation, low detection accuracy, and inability to quantify absorption in the testing of free carrier absorption of polycrystalline silicon layers.

The application discloses a high-refractive-index extended-cavity vertical-cavity surface-emitting laser, a preparation method and application thereof, and relates to the technical field of semiconductors. The application solves the problems of a large line width of an existing vertical-cavity surface-emitting laser and difficulty in controlling a narrow line width in the prior art. The laser comprises, from top to bottom, a top electrode, a p-type Bragg mirror group, an oxidation layer, an active region, an n-type extension layer, an n-type Bragg mirror group, a substrate and a bottom electrode, wherein the n-type extension layer is Al y Ga 1‑ y As, and y is 0.1-0.9. By arranging the n-type extension layer and setting the n-type extension layer to a specific material, resistance and free carrier absorption in the extension layer are inhibited, the effective cavity length of the laser is effectively increased, the resonant cavity length is increased, the output power is increased, the line width enhancement factor alpha is reduced, and the spectral line width is narrowed.

The utility model discloses a passivation contact cell with a selective polycrystalline silicon layer. A selective polycrystalline silicon layer doping technology is adopted in the cell, doped polycrystalline silicon layers are arranged in a local area of a polycrystalline silicon layer at intervals, local grooves are formed in a back passivation antireflection layer at intervals, metal grid lines are in contact with the doped polycrystalline silicon layers only in groove areas and in non-local opening areas, and the metal grid lines are suspended on an antireflection film layer. And no contact with the doped polycrystalline silicon layer is formed. As the intrinsic polycrystalline silicon layer does not have a free carrier absorption phenomenon, parasitic absorption cannot be formed on photons of which the wavelength is greater than 950nm, and optical loss can be remarkably reduced. The arrangement of the local opening grooves can reduce the absorption of the metal grid lines to long-wave photons, the metal grid lines in the non-local opening area and the antireflection film layer can form a back reflector, the long-wave photons can be reflected back to the silicon substrate more effectively to be absorbed and utilized again, and the utilization rate of the long-wave photons is improved.

This invention discloses a vertical-cavity surface-emitting laser (VCSEL), comprising, from bottom to top, a substrate, a lower grating layer, an active layer, a contact layer, and an upper grating layer. The upper grating layer protrudes from the middle of the contact layer, and a first step is formed between the sidewall of the upper grating layer and the contact layer. The contact layer and the active layer protrude from the middle of the lower grating layer, and a second step is formed between the sidewall of the contact layer and the active layer and the lower grating layer. A p-type electrode is also provided on the contact layer, and a heat dissipation electrode is also provided on the p-type electrode, extending from the first step to the second step. This invention places the p-type electrode on the contact layer, thereby reducing the distance between the p-type electrode and the active layer, effectively reducing free carrier absorption and self-heating. Furthermore, the presence of a heat dissipation electrode on the p-type electrode further increases the contact surface between the heat dissipation electrode and the external environment, improving the heat dissipation performance of the VCSEL.

A potential difference measurement device (101) comprises: a light source (1); a semiconductor optical element (3) in which free carriers generated by the presence of charged particles absorb incident light incident from the light source (1), thereby reducing the intensity of emitted light that is emitted, relative to the intensity of the incident light; a detector (5) that detects the intensity of the emitted light; and a calculation unit (6) that calculates the intensity difference of the emitted light between before and after the reduction. The intensity difference varies according to the potential difference between outer space and a charged body (10) charged by the charged particles. The calculation unit (6) measures the potential difference by calculating the intensity difference in a state in which the semiconductor optical element (3) is disposed on the charged body (10) and the surface potential of the semiconductor optical element (3) is set to the same potential as the potential of the charged body (10) or to a potential having a predetermined potential difference with the potential of the charged body (10).

The present invention discloses a fully silicon photodetector based on compensated doping and a preparation method thereof, belonging to the field of optoelectronic devices. The fully silicon photodetector includes a compensated doping absorption region and P++ and N++ heavily doped regions for collecting current. On the one hand, through the compensated doping method of mixing P-type and N-type, a defect density exceeding that of traditional single doping is introduced inside the silicon waveguide, and at the same time, an absorption region with the properties of an intrinsic semiconductor is formed, avoiding free carrier absorption that contributes nothing to light detection. On the other hand, the defect density at the interface is increased and the interaction between the defect and light is enhanced through the slit waveguide. Thus, the fully silicon photodetector can utilize the defects introduced in the silicon waveguide and the enhanced interaction between light and defects to achieve light detection in the optical communication band (1.3 - 1.6 μm). In addition, the preparation process of the present invention is fully compatible with the CMOS process, without introducing other materials, and has the advantages of low cost and high integration.

Disclosed herein are methods, structures, apparatus and devices for the termination of unused waveguide ports in planar photonic integrated circuits with doped waveguides such that free-carrier absorption therein may advantageously absorb any undesired optical power resulting in a significant reduction of stray light and resulting reflections.