SYSTEMS AND METHODS OF LASER TEXTURING OF MATERIAL SURFACES AND THEIR APPLICATIONS

• US 20130020297A1
• Filed: 09/26/2012
• Published: 01/24/2013
• Est. Priority Date: 12/21/2005
• Status: Active Grant

• Current Assignee: University of Virginia Patent Foundation (University of Virginia)
• Original Assignee: University of Virginia Patent Foundation (University of Virginia)
• Inventors: Gupta, Mool C., Nayak, Barada K.
• Granted Patent: US 8,846,551 B2
• Time in Patent Office: Days
• US Class Current: 219/121.72
• CPC Class Codes: B23K 26/12 in a special atmosphere, e.g. in an enclosure
• CPC Class Codes: B23K 26/122 in a liquid, e.g. underwater
• CPC Class Codes: B23K 26/1224 in vacuum
• CPC Class Codes: B23K 26/127 in an enclosure
• CPC Class Codes: B23K 26/355 Texturing
• CPC Class Codes: B23K 26/3584 Increasing rugosity, e.g. roughening
• CPC Class Codes: Y10S 977/901 having step or means utilizing electromagnetic property, e.g. optical, x-ray, electron beamm

Abstract

The surface of a material is textured and by exposing the surface to pulses from an ultrafast laser. The laser treatment causes pillars to form on the treated surface. These pillars provide for greater light absorption. Texturing and crystallization can be carried out as a single step process. The crystallization of the material provides for higher electric conductivity and changes in optical and electronic properties of the material. The method may be performed in vacuum or a gaseous environment. The gaseous environment may aid in texturing and/or modifying physical and chemical properties of the surfaces. This method may be used on various material surfaces, such as semiconductors, metals and their alloys, ceramics, polymers, glasses, composites, as well as crystalline, nanocrystalline, polycrystalline, microcrystalline, and amorphous phases.

Claims

1. A method for texturing a surface of a material, comprising:

providing a gaseous or vacuum environment in an area around the surface of the material;

irradiating a portion of the surface with laser pulses, wherein the laser pulses have;

a laser pulse energy density of about 0.05 J/cm² to about 5 J/cm²,

a wavelength of about 200 nm to about 2000 nm,

a pulse width greater than 0 ns and less than about 30 ns; and

wherein the method produces a periodic array of pillars or a non-periodic array of pillars on the surface, resulting in changes in properties of the surface.

2. The method of claim 1, wherein the laser pulses are sent at a repetition rate of about 1 Hz to 100 MHz.

3. The method of claim 1, wherein the laser pulses are sent at a repetition rate of about 20 Hz to 600 kHZ.

4. The method of claim 1, wherein the laser pulses are sent at a repetition rate of about 10 Hz to 40 Hz.

5. The method of claim 1, wherein the laser pulses are sent at a repetition rate of about 500 kHz to 700 kHz.

6. The method of claim 1, further comprising the step of:

annealing said surface at less than about 1,500 degC after laser texture.

7. The method of claim 6, where said annealing occurs for a duration from about 1 second to about 2 hours.

8. The method of claim 6, where said annealing occurs for a duration from about 1 second to about 1 hour.

9. The method of claim 6, where said annealing occurs for a duration from 1 second to about 10 minutes.

10. The method of claim 1, wherein the laser spot size is about 50 um to about 200 um having a substantially uniform energy distribution.

11. The method of claim 1, wherein the laser spot size on the surface is between about 3 um to 8 mm by between about 3 um to 8 mm.

12. The method of claim 1, wherein the laser spot size on the surface has an area of about 10,000 um² having a substantially uniform energy distribution.

13. The method of claim 1, wherein the laser pulses have a wavelength of about 300 nm to 400 nm.

14. The method of claim 1, wherein the laser pulses have a laser pulse energy density of about 1.6 J/cm² to 2 J/cm².

15. The method of claim 1, wherein the laser pulses have a pulse width of about 3.5 ns.

16. The method of claim 1, wherein the laser pulses have a pulse width of about lns.

17. The method of claim 1, further comprising the step of:

moving at least one of the surface or the laser beam relative to each other to allow the laser pulses to irradiate a surface area larger than the laser beam spot size.

18. The method of claim 1, wherein said material surface comprises at least one of the following:

semiconductor material, metallic, dielectric material, alloy material, or polymer material.

19. The method of claim 1, wherein said laser pulses have:

about 1 to 120 laser pulses to irradiate the material,

said wavelength of about 337 nm,

said pulse energy density of about 1.6 J/cm² to 2 J/cm², and

said pulse width of about 3.5 ns.

20. The method of claim 19, wherein said number of laser pulses is about 100.

21. The method of claim 1, wherein said laser pulses have:

about 80 to 120 laser pulses to irradiate the material.

23. The method of using the textured surface of claim 1 to provide a high-efficiency heat sink for an electronic or optoelectronic device.

24. The method of using the textured surface of claim 1 to provide a very high electric field for electron emission.

25. The method of using the textured surface of claim 1 to generate catalytic activity.

26. The method of using the textured surface of claim 1 to perform osteointegration of a body implant.

27. The method of using the textured surface of claim 1 to control the flow of air or fluid over the surface.

28. The method of using the textured surface of claim 1 to create a two-dimensional array of micro or nano dimensioned ordered tips.

29. The method of using the textured surface of claim 1 to manufacture an optical beam block which absorbs substantially all light from the visible to the far-infrared.

30. The method of using the textured surface of claim 1 in micro fluidic applications.

31. The method of using the textured surface of claim 1 to provide a radiation shield which operates in a broad spectral range.

32. The method of using the textured surface of claim 1 to provide an infrared sensor.

33. The method of using the textured surface of claim 1 to provide an element to control light reflection or transmission in an optical device.

34. The method of using the textured surface of claim 1 to provide a template for optoelectronic devices.

35. The method of claim 34, wherein said optoelectronic devices comprises at least one of:

photodetector, photovoltaic cell, photoconductive devices, sensor application, sensor, optical device, electronic device, or photonic device.

36. The method of using the textured surface of claim 1 to provide an electrical device.

37. The method of claim 36, wherein, said electrical device provides at least one of electrical resistance or charge carrier control type.

38. The method of using the textured surface of claim 1 to provide a laser device to control optical properties.

39. The method of using the textured surface of claim 1 to provide an opto-mechanical device.

40. The method of claim 39, wherein said opto-mechanical device provides electrical power conversion for mechanical motion.

41. The method of using the textured surface of claim 1 to provide a mechanical device.

42. The method of claim 41, wherein said mechanical device can be used to control tribological properties required for said mechanical device.

22. The method of 21, wherein said number of laser pulses is about 100.

43. A system for texturing a surface of a material comprising:

a gaseous or vacuum environment encompassing the material;

a base for retaining the surface; and

an energy source configured to provide a radiation source, said radiation source configured to irradiate a portion of the surface with laser pulses, said laser pulses configured to provide;

a laser pulse energy density of about 0.05 J/cm² to about 5 J/cm²;

a wavelength of about 200 nm to about 2000 nm; and

a pulse width greater than 0 ns and less than about 30 ns;

resulting in the formation of a periodic array of pillars or a non-periodic array of pillars on the surface.

44. The system of claim 43, wherein the laser pulses are sent at a repetition rate of about 1 Hz to 100 MHz.

45. The system of claim 43, wherein the laser pulses are sent at a repetition rate of about 20 Hz to 600 kHZ.

46. The system of claim 43, wherein the laser pulses are sent at a repetition rate of about 10 Hz to 40 Hz.

47. The system of claim 43, wherein the laser pulses are sent at a repetition rate of about 500 kHz to 700 kHz.

48. The system of claim 43, further comprising:

an annealing means for the annealing said surface at less than about 1,500 degC, whereby said annealing occurs after laser texture.

49. The system of claim 48, where said annealing occurs for a duration from about 1 second to about 2 hours.

50. The system of claim 48, where said annealing occurs for a duration from about 1 second to about 1 hour.

51. The system of claim 48, where said annealing occurs for a duration from 1 second to about 10 minutes.

52. The system of claim 43, wherein the laser spot size on said surface is about 50 um by about 2,000 um having a substantially uniform energy distribution.

53. The system of claim 43, wherein the laser spot size on said surface is about 50 um by about 200 um having a substantially uniform energy distribution.

54. The system of claim 43, wherein the laser spot size on the surface is between about 3 um to 8 mm by between about 3 um to 8 mm.

55. The system of claim 43, wherein the laser spot size on the surface has an area of about 10,000 um² having a substantially uniform energy distribution.

56. The system of claim 43, wherein the laser pulses have a wavelength of about 300 nm to 400 nm.

57. The system of claim 43, wherein the laser pulses have a laser pulse energy density of about 1.6 J/cm² to 2 J/cm².

58. The system of claim 43, wherein the laser pulses have a pulse width of about 3.5 ns.

59. The system of claim 43, wherein the laser pulses have a pulse width of about 1 ns.

60. The system of claim 43, wherein:

said base or the laser beam are configured to move relative to each other to allow the laser pulses to irradiate a larger surface area than the laser beam spot size.

61. The system of claim 43, wherein said material surface comprises at least one of the following:

semiconductor material, metallic material, dielectric material, alloy material, or polymer material.

62. The system of claim 43, wherein said laser pulses have:

about 80 to 120 laser pulses to irradiate the material,

said wavelength of about 337 nm,

said pulse energy density of about 1.6 J/cm² to 2 J/cm², and

said pulse width of about 3.5 ns.

63. The system of claim 62, wherein said number of laser pulses is about 100.

64. The system of claim 43, wherein said laser pulses have:

about 80 to 120 laser pulses to irradiate the material.

65. The system of 64, wherein said number of laser pulses is about 100.