公开(公告)号：US11894483B2

公开(公告)日：2024-02-06

申请号：US17864324

申请日：2022-07-13

Applicant: BEIJING UNIVERSITY OF TECHNOLOGY

Inventor： Lingfei Ji ,  Weigao Sun

IPC: H01L31/18 ,  H01L31/0304

CPC classification number: H01L31/1856 ,  H01L31/03044 ,  H01L31/1896

Abstract: The invention provides a laser rapid fabrication method for flexible gallium nitride (GaN) photodetector which comprises the following steps: (1) bonding a flexible substrate to a GaN epitaxial wafer; (2) adjusting the focal plane position of a light beam, and ensuring that the light beam is incident from the side of a GaN epitaxial wafer substrate; (3) enabling the light beam to perform scanning irradiation from the edge of a sample structure obtained in the step (1); (4) adjusting the process parameters, and scanning irradiation in the reverse direction along the path in the step (3); (5) remove the original rigid transparent substrate of the epitaxial wafer to obtain a Ga metal nanoparticle/GaN film/flexible substrate structure; and (6) preparing interdigital electrodes on the surfaces of the Ga metal nanoparticles obtained in the step (5). The flexible GaN photodetector with Ga metal nanoparticle in-situ distribution detection surface is prepared in one step through laser technology, the process is simplified, meanwhile, the surface of the detector is induced to form the surface plasmon resonance effect, the light absorption and light response performance is greatly enhanced, and the flexible gallium nitride photodetector is suitable for industrial production.

公开(公告)号：US20190366484A1

公开(公告)日：2019-12-05

申请号：US15771994

申请日：2017-03-24

Applicant: Beijing University of Technology

Inventor： Lingfei Ji ,  Tianyang Yan ,  Lin Li ,  Na An ,  Zhenyuan Lin ,  Wenhao Wang

IPC: B23K26/53 ,  B23K26/70 ,  C03C15/00 ,  C03B33/02

Abstract: The present disclosure relates to a method for high precision laser processing of sapphire with submicron roughness cutting surface using a picosecond pulse laser which has high transmittance wavelength to sapphire. The laser triggers ultrafine phase transformation points or electronic state removal points from a lower surface of sapphire. After elevating focal points, a trace which is parallel to laser incident direction is formed. Under a chemical corrosion environment, points of the laser trace are arranged to intersect with other another according to the cutting route to form the corresponding phase transformation region and electronic state removal region. At the same time, by utilizing the catalysis effect of microthermal effect of picosecond laser on chemical corrosion, separation of the sapphire sample along the processing path is obtained. The present disclosure overcomes the limitation of Gaussian beam focusing mode and realizes high precision sapphire cutting with zero tapers and no heat-affected zone. Cutting of hyperfine sapphire and other materials with the high quality cutting surface in micron and submicron ranges with no limitation on the thickness and process path is achieved.

公开(公告)号：US10596663B2

公开(公告)日：2020-03-24

申请号：US15771994

申请日：2017-03-24

Applicant: Beijing University of Technology

Inventor： Lingfei Ji ,  Tianyang Yan ,  Lin Li ,  Na An ,  Zhenyuan Lin ,  Wenhao Wang

IPC: B23K26/53 ,  B23K26/70 ,  C03B33/02 ,  C03C15/00 ,  B23K103/00

Abstract: The present disclosure relates to a method for high precision laser processing of sapphire with submicron-order section plane using a picosecond-order pulse laser which has high transmittance wavelength to sapphire. The laser triggers ultrafine phase transformation points or electronic state removal points from a lower surface of sapphire. After elevating focal points, a trace which is parallel to laser incident direction is formed. Under a chemical corrosion environment, points of the laser trace are arranged to intersect with other another according to the cutting route to form the corresponding phase transformation region and electronic state removal region. At the same time, by utilizing the catalysis effect of microthermal effect of picosecond laser on chemical corrosion, separation of the sapphire sample along the processing path is obtained. The present disclosure overcomes the limitation of Gaussian beam focusing mode and realizes high precision sapphire cutting with zero tapers and no heat-affected zone. Cutting of hyperfine sapphire and other materials with the high quality cutting surface in micron and submicron ranges with no limitation on the thickness and process path is achieved.

公开(公告)号：US11014197B2

公开(公告)日：2021-05-25

申请号：US16727726

申请日：2019-12-26

Applicant: BEIJING UNIVERSITY OF TECHNOLOGY

Inventor： Lingfei Ji ,  Ximin Zhang ,  Wenhao Wang ,  Tianyang Yan ,  Rui Ma

IPC: B23K26/354 ,  B23K26/00

Abstract: The invention disclose a picosecond-nanosecond laser composite asynchronous ceramics polishing method. First, a picosecond laser is used to scan and irradiate the ceramic surface along the scanning path. At the same time, ceramic surface is initially flattened and the electronic state of materials is removed by picosecond laser to produce micro-nanoparticles. Micro-nanoparticles exist as ionized state in the adjacent space region of irradiated ceramics surface. Then, low energy density nanosecond laser is used according to a preset time to irradiate and melt these micro-nanoparticles which can easily form a dense and smooth fine crystal melting layer to achieve the polishing effect. The present disclosure fixes the generation of micro-cracks and pores in traditional laser polishing process. It overcomes the shortcomings of traditional laser polishing such as large thermal influence zone, easy to generate micro-cracks and pores on the surface, etc. High efficiency and high precision submicron level fine polishing with very low material removal amount is realized.

公开(公告)号：US20200269355A1

公开(公告)日：2020-08-27

申请号：US16727726

申请日：2019-12-26

Applicant: BEIJING UNIVERSITY OF TECHNOLOGY

Inventor： Lingfei Ji ,  Ximin Zhang ,  Wenhao Wang ,  Tianyang Yan ,  Rui Ma

IPC: B23K26/354 ,  B23K26/00

Abstract: The invention disclose a picosecond-nanosecond laser composite asynchronous ceramics polishing method. First, a picosecond laser is used to scan and irradiate the ceramic surface along the scanning path. At the same time, ceramic surface is initially flattened and the electronic state of materials is removed by picosecond laser to produce micro-nanoparticles. Micro-nanoparticles exist as ionized state in the adjacent space region of irradiated ceramics surface. Then, low energy density nanosecond laser is used according to a preset time to irradiate and melt these micro-nanoparticles which can easily form a dense and smooth fine crystal melting layer to achieve the polishing effect. The present disclosure fixes the generation of micro-cracks and pores in traditional laser polishing process. It overcomes the shortcomings of traditional laser polishing such as large thermal influence zone, easy to generate micro-cracks and pores on the surface, etc. High efficiency and high precision submicron level fine polishing with very low material removal amount is realized.

公开(公告)号：US20190210156A1

公开(公告)日：2019-07-11

申请号：US15574503

申请日：2016-11-18

Applicant: Beijing University of Technology

Inventor： Lingfei Ji ,  Wenhao Wang ,  Tianyang Yan ,  Rui Jiang ,  Sicong Wang ,  Zhenyuan Lin ,  Qiang Yang

IPC: B23K26/40 ,  B23K26/082

CPC classification number: B23K26/40 ,  B23K26/082 ,  B23K26/38 ,  B23K26/402 ,  B23K26/702 ,  B23K37/0443 ,  B23K2101/20

Abstract: The present invention discloses a work fixture, a device and a method for machining the cutting edge of cutting tools. The work fixture comprising: rotatable beveled base inside the fixture shell, the angle of the beveled base can be adjusted by the angle adjusting device; a feeding plate on the beveled base, on which a plurality of grooves are equispaced on the plate for clamping the cutting tools to be machined and completing the machining of the cutting edge. The device and the method of the present invention comprising: a controller being connected with a laser and a laser galvanometer, respectively; the beam of the laser sequentially passing through the reflection lens and the laser galvanometer to make the incident direction perpendicular to the datum plane and shot on the cutting tool to be machined on the feeding plate, and completing the machining of the cutting edge. Wherein, the laser parameters include a wavelength of 100 nm˜1064 nm, 10.6 um; an average pulse power of 1 W˜500 W; a pulse width of 10 ps˜300 ns; and a repetition frequency of 200 kHz˜10 MHz. The present invention can obtain the required cutting edge by laser cutting the cutting part once, with which the output and the efficiency are greatly improved and the cost is reduced. All the indicators, such as the obtained cutting edge, the roughness and the machining precision are also improved significantly.