Systems and Methods of Laser Texturing of Material Surfaces and their Applications

• US 20100143744A1
• Filed: 03/06/2008
• Published: 06/10/2010
• Est. Priority Date: 03/09/2007
• Status: Abandoned Application

• Current Assignee: University of Virginia
• Original Assignee: University of Virginia Patent Foundation (University of Virginia)
• Inventors: Gupta, Mool C., Nayak, Barada K.
• Application Number:
  US12/530,313
• Publication Number:
  US 20100143744A1
• Time in Patent Office: Days
• US Class Current: 428/601
• CPC Class Codes: B23K 2103/16 Composite materials , e.g. fibre reinforced
• CPC Class Codes: B23K 2103/42 Plastics B23K2103/16 takes precedence
• CPC Class Codes: B23K 2103/50 Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
• CPC Class Codes: B23K 2103/52 Ceramics
• CPC Class Codes: B23K 26/0006 taking account of the properties of the material involved B23K26/32, B23K26/40 take precedence
• CPC Class Codes: B23K 26/355 Texturing
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G02B 6/1225 comprising photonic band-gap structures or photonic lattices
• CPC Class Codes: H01L 21/02422 Non-crystalline insulating materials, e.g. glass, polymers
• CPC Class Codes: H01L 21/02532 Silicon, silicon germanium, germanium
• CPC Class Codes: H01L 21/02587 Structure
• CPC Class Codes: H01L 21/02686 Pulsed laser beam
• CPC Class Codes: H01L 31/0236 Special surface textures
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy
• CPC Class Codes: Y10T 428/12396 Discontinuous surface component
• CPC Class Codes: Y10T 428/24479 including variation in thickness

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 short laser pulses; and

moving at least one of the surface or a laser beam relative to each other to allow the short laser pulses to irradiate the surface;

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 said material comprises at least one of metal, alloys, semiconductor, ceramic, glasses and polymer, or any combination thereof.

3. The method of claim 1, wherein said surface remains stationary and said laser beam moves.

4. The method of claim 1, wherein said laser beam remains stationary and said surface moves.

5. The method of claim 1, wherein said laser beam and said surface moves.

6. The method of claim 1, wherein moving comprises translating in the x-y direction or translating or rotating in the z-direction or both translating in the x-y direction and translating or rotating or moving in the z direction.

7. The method of claim 1 wherein said laser beam moves relative to said surface by using a mirror, galvo-head, an optical element, or any combination thereof to change the path of said laser.

8. The method of claim 1, wherein the surface is in air at atmospheric pressure.

9. The method of claim 1, wherein the laser pulses have a duration of between about one femtosecond and about one microsecond.

10. The method of claim 1, wherein the laser pulses have a laser pulse energy density of between about 0.01 J/cm² and about 20 J/cm².

11. The method of claim 1, wherein the laser pulses have a laser pulse energy density of between about 0.1 J/cm² and about 1.4 J/cm².

12. The method of claim 1, wherein the laser pulses have a wavelength of between about 190 and about 11,000 nm.

13. The method of claim 1, wherein the laser pulses have a wavelength of between about 200 and about 1600 nm.

14. The method of claim 1, wherein irradiating the surface further comprises scanning the surface in a plurality of directions.

15. The method of claim 1, wherein irradiating the surface further comprises scanning the surface in a single direction a plurality of times.

16. The method of claim 1, further comprising controlling a surface texture by controlling a polarization state of the laser pulses.

17. The method of claim 1, further comprising controlling an electrical conductivity of the material by controlling texturing parameters.

18. The method of claim 1, wherein irradiating the surface further comprises at least partially crystallizing the irradiated surface.

19. The method of claim 1, further comprising controlling a spacing between adjacent pillars by controlling a wavelength of the laser pulses, a laser pulse energy density, and a number of laser pulses.

20. The method of claim 19, wherein said controlling further comprises controlling the spacing between adjacent pillars and/or their orientation by controlling an angle of incidence of said laser pulses or inclining the sample or combination thereof.

21. The method of claim 1, wherein the inert gas comprises at least one of air, sulfur hexafluoride gas, hydrogen chloride gas, helium gas, argon gas, other fluoride based gases, or other chloride based gases, or other chemical gases.

22. The method of claim 1, wherein the gaseous or vacuum environment has a pressure in the range of about 8 to about 10 Torr.

23. The method of claim 1, wherein the gaseous or vacuum environment has a pressure in the range below atmosphere to about several atmospheres.

24. The method of claim 1, wherein the gaseous or vacuum environment comprises a gaseous plasma.

25. The method of using the textured surface of claim 1 to provide a photovoltaic device.

26. The method of using the textured surface of claim 1 to provide a photodetector.

27. The method of claim 1, wherein the changed properties are at least one of optical properties, thermal properties, tribological properties, mechanical properties, electronic properties, or electrical properties.

28. The method of claim 1, wherein the method additionally produces nanospikes atop the pillars.

30. The method of claim 1, further comprising controlling a texture of said array of pillars by controlling the angle of incidence between said laser beam and said surface of the material.

31. The method of claim 30, wherein said controlling said angle of incidence comprises tilting the surface or laser beam relative to one another.

32. The method of claim 1, further comprising controlling of pillars by controlling said gaseous or vacuum environment.

33. The method of claim 1, further comprising controlling a periodicity of pillars by controlling process parameters.

34. The method of claim 1, further comprising controlling the formation of said pillars by post irradiation processing.

68. The method of using the textured surface of claim 1 or 36 to provide a high-efficiency heat sink for an electronic or optoelectronic device.

69. The method of using the textured surface of claim 1 or 36 to provide a very high electric field for electron emission.

70. The method of using the textured surface of claim 1 or 36 to generate catalytic activity.

71. The method of using the textured surface of claim 1 or 36 to perform osteointegration of a body implant.

72. The method of using the textured surface of claim 1 or 36 to control the flow of air or fluid over the surface.

73. The method of using the textured surface of claim 1 or 36 to create a two-dimensional array of micro or nano dimensioned ordered tips.

74. The method of using the textured surface of claim 1 or 36 to manufacture an optical beam block which absorbs substantially all light from the visible to the far-infrared.

75. The method of using the textured surface of claim 1 or 36 in micro fluidic applications.

76. The method of claim 1 or 36, further comprising controlling a color of the surface.

77. The method of using the textured surface of claim 1 or 36 to produce a master for replication.

78. The method of claim 1 or 36, further comprising processing the surface with chemical etching to provide nano or micro pores on the surface.

79. The method of claim 1 or 36, further comprising controlling an emissivity of the surface.

80. The method of claim 1 or 36, further comprising writing text or images on the surface by controlling a light reflectivity.

81. The method of using the textured surface of claim 1 or 36 to provide a radiation shield which operates in a broad spectral range.

82. The method of using the textured surface of claim 1 or 36 to provide an infrared sensor.

83. The method of using the textured surface of claim 1 or 36 to provide an element to control light reflection or transmission in an optical device.

84. The method of using the textured surface of claim 1 or 36 to provide a template for optoelectronic devices.

85. The method of claim 84, wherein said optoelectronic devices comprises at least one of:

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

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

87. The method of claim 86, wherein, said electrical device provides at least one of electrical resistance or charge carrier control type.

88. The method of using the textured surface of claim 1 or 36 to provide a laser device to control optical properties.

89. The method of claim 88, wherein said laser comprises light emitting diode (LED) devices.

90. The method of using the textured surface of claim 1 or 36 to provide an opto-mechanical device.

91. The method of claim 90, wherein said opto-mechanical device provides electrical power conversion for mechanical motion.

92. The method of using the textured surface of claim 1 or 36 to provide a mechanical device.

93. The method of claim 92, wherein said mechanical device can be used to control tribological properties required for said mechanical device.

103. The method claim 1, wherein said method produces both a periodic array of pillars and a non-periodic array of pillars on the surface, resulting in changes in properties of the surface.

104. The method of claim 1, wherein the laser pulses have a duration of between about 0.1 femtosecond and about one millisecond.

29. The method of claim 29, further comprising sharpening the nanospikes by at least one of chemical etching or ion etching, or any combination thereof after irradiating the surface.

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

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

irradiating a portion of the surface with short laser pulses while simultaneously crystallizing the portion of the surface; and

moving at least one of the surface and a laser beam relative to each other to allow the short laser pulses to irradiate another portion of the surface while simultaneously crystallizing the other portion of the surface;

wherein the method produces pillars on the surface, resulting in changes in properties of the surface.

36. A method for texturing a metallic surface, comprising:

irradiating a portion of the metallic surface with short laser pulses; and

moving at least one of the surface and a laser beam relative to each other to allow the short laser pulses to irradiate another portion of the surface;

wherein the method produces pillars on the surface, resulting in changes in properties of the surface.

37. The method of claim 36, wherein said material comprises at least one of metal, alloys, semiconductor, ceramic, and polymer, or any combination thereof.

38. The method of claim 36, wherein said surface remains stationary and said laser beam moves.

39. The method of claim 36, wherein said laser beam remains stationary and said surface moves.

40. The method of claim 36, wherein said laser beam and said surface moves.

41. The method of claim 36, wherein moving comprises translating in the x-y direction or translating or rotating in the z-direction or both translating in the x-y direction and translating or rotating or moving in the z direction rotating.

42. The method of claim 36 wherein said laser beam moves relative to said surface by using a mirror, galvo-head, an optical element, or any combination thereof to change the path of said laser.

43. The method of claim 36, wherein the method additionally produces nanospikes atop the pillars.

44. The method of claim 36, further comprising sharpening the nanospikes by at least one of chemical etching and ion etching after irradiating the surface.

45. The method of claim 36, wherein the laser pulses have a duration of between one femtosecond and one microsecond.

46. The method of claim 36, wherein irradiating the surface further comprises scanning the surface in a single direction a plurality of times.

47. The method of claim 36, wherein the pillars are produced in a periodic or non-periodic array.

48. The method of claim 36, further comprising providing an atmosphere of gas in an area around the surface.

49. The method of claim 48, wherein the atmosphere of gas comprises at least one of sulfur hexafluoride gas, hydrogen chloride gas, helium gas, argon gas, other fluoride based gasses, or other chloride based gasses, or other chemical gases.

50. The method of claim 48, wherein the atmosphere of gas has a pressure in the range of below atmosphere to about several atmospheres.

51. The method of claim 48, wherein the atmosphere gas comprises a gaseous plasma.

52. The method of claim 36, wherein the surface is in air at atmospheric pressure.

53. The method of claim 36, wherein the laser pulses have a duration of between about one femtosecond and about one microsecond.

54. The method of claim 36, wherein the laser pulses have a laser pulse energy density of between about 0.01 J/cm² and about 4 J/cm².

55. The method of claim 36, wherein the laser pulses have a laser pulse energy density of between about 0.1 J/cm² and about 1.4 J/cm².

56. The method of claim 36, wherein the laser pulses have a wavelength of between about 190 and about 11,000 nm.

57. The method of claim 36, wherein the laser pulses have a wavelength of between about 200 and about 1600 nm.

58. The method of claim 36, wherein irradiating the surface further comprises scanning the surface in a plurality of directions.

59. The method of claim 36, further comprising controlling a surface texture by controlling a polarization state of the laser pulses.

60. The method of claim 36, further comprising controlling an electrical conductivity of the material by controlling texturing parameters.

61. The method of using the textured surface of claim 36 to provide adhesion.

62. The method of claim 36, wherein the changed properties are at least one of optical properties, thermal properties, tribological properties or electrical properties.

63. The method of claim 36, further comprising controlling a texture of said array of pillars by controlling the angle of incidence between said laser beam and said surface of the material.

64. The method of claim 63, wherein said controlling said angle of incidence comprises tilting the surface or laser beam relative to one another.

65. The method of claim 36, further comprising controlling a periodicity of pillars by controlling said gaseous or vacuum environment.

66. The method of claim 36, further comprising controlling a periodicity of pillars by controlling process parameters.

67. The method of claim 36, further comprising controlling the formation of said pillars by post irradiation processing.

94. A semiconductor surface, comprising a portion on which pillars are formed with nanospikes atop the pillars by irradiating the surface with short laser pulses in a vacuum or gaseous environment surrounding the surface.

95. A metallic surface, comprising a portion on which pillars are formed by irradiating the surface with short laser pulses.

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

a chamber in an area around the surface of the material to provide a gaseous or vacuum environment;

an energy source providing a power supply for a radiation source, said radiation source for irradiating at least a portion of the surface;

a base for retaining said surface, said base or radiation source adapted to move relative to one another for irradiation wherein a periodic array of pillars or a non-periodic array of pillars on the surface, resulting in changes in properties of the surface.

97. The system claim 96, wherein said both a periodic array of pillars and a non-periodic array of pillars on the surface are produced, resulting in changes in properties of the surface.

98. The system of claim 96, wherein said radiation source comprises a laser.

99. The system of claim 96, wherein said chamber provides a means for controlling the environment therein.

100. The system of claim 96, wherein said base is movable in the x-y direction or rotatable or movable in the z direction or both movable in the x-y direction and movable or rotatable in the z direction.

120. The surface of claim 96, wherein said radiation comprises at least one of:

ion, plasma, electron or microwave or any combination thereof.

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

a chamber in an area around the surface of the material to provide a gaseous or vacuum environment;

an energy source providing a power supply for a radiation source, said radiation source for irradiating at least a portion of the surface; and

a base for retaining said surface, said base or radiation source adapted to move relative to one another for irradiation wherein the portion of the surface is crystallized during irradiation.

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

a chamber in an area around the surface of the material to provide a gaseous or vacuum environment;

an energy source providing a power supply for a radiation source, said radiation source for irradiating at least a portion of the surface; and

a base for retaining said surface, said base or radiation source adapted to move relative to one another for irradiation wherein pillars are produces on said portion of the surface, resulting in changes in properties of the surface

105. A surface, comprising a portion on which pillars are formed with nanospikes atop the pillars by irradiating the surface with short laser pulses in a vacuum or gaseous environment surrounding the surface, wherein said surface comprises at least one of metal, metal alloys, ceramic, glasses or polymer, or any combination thereof.

106. A surface, comprising a portion on which pillars are formed by irradiating the surface with short laser pulses, wherein said surface comprises at least one of metal alloys, semiconductor, ceramic, glasses or polymer, or any combination thereof.

107. 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 energy pulses; and

moving at least one of the surface or an energy beam relative to each other to allow the energy pulses to irradiate the surface;

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.

108. The method of claim 107, wherein said energy pulse comprises at least one of:

ion, plasma, electron or microwave or any combination thereof.

109. The method of claim 107, wherein said energy pulse comprises laser.

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

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

irradiating a portion of the surface with energy pulses while simultaneously crystallizing the portion of the surface; and

moving at least one of the surface and an energy beam relative to each other to allow the short energy pulses to irradiate another portion of the surface while simultaneously crystallizing the other portion of the surface; and

wherein the method produces pillars on the surface, resulting in changes in properties of the surface.

111. The method of claim 110, wherein said energy pulse comprises at least one of:

ion, plasma, electron or microwave or any combination thereof.

112. The method of claim 110, wherein said energy pulse comprises laser.

113. A method for texturing a metallic surface, comprising:

irradiating a portion of the metallic surface with energy pulses; and

moving at least one of the surface and an energy beam relative to each other to allow the energy pulses to irradiate another portion of the surface;

wherein the method produces pillars on the surface, resulting in changes in properties of the surface.

114. The method of claim 113, wherein said energy pulse comprises at least one of:

ion, plasma, electron or microwave or any combination thereof.

115. The method of claim 113, wherein said energy pulse comprises laser.

116. A surface, comprising a portion on which pillars are formed with nanospikes atop the pillars by irradiating the surface with energy pulses in a vacuum or gaseous environment surrounding the surface, wherein said surface comprises at least one of metal, metal alloys, ceramic, semiconductor glasses or polymer, or any combination thereof.

117. The surface of claim 116, wherein said energy pulse comprises at least one of:

ion, plasma, electron or microwave or any combination thereof.

118. A surface, comprising a portion on which pillars are formed by irradiating the surface with energy pulses, wherein said surface comprises at least one of metal, metal alloys, semiconductor, ceramic, glasses or polymer, or any combination thereof.

119. The surface of claim 118, wherein said energy pulse comprises at least one of:

ion, plasma, electron or microwave or any combination thereof.

121. A method for producing a structure or texture, said method comprising:

controlling laser texturing process and/or crystallizing process by varying the spatial profile of the laser pulse.

122. A method for producing a structure or texture, said method comprising:

controlling surface texture and/or crystallization by preheating the sample and providing additional energy by the laser beam.