Classifications

• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
  • H10F77/00—Constructional details of devices covered by this subclass
  • H10F77/20—Electrodes
  • H10F77/244—Electrodes made of transparent conductive layers, e.g. transparent conductive oxide [TCO] layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
  • B82Y10/00—Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• • G—PHYSICS
  • G02—OPTICS
  • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
  • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
  • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
  • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
  • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
  • G02F1/1333—Constructional arrangements; Manufacturing methods
  • G02F1/1343—Electrodes
  • G02F1/13439—Electrodes characterised by their electrical, optical, physical properties; materials therefor; method of making
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
  • H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
  • H01G9/20—Light-sensitive devices
  • H01G9/2027—Light-sensitive devices comprising an oxide semiconductor electrode
  • H01G9/2031—Light-sensitive devices comprising an oxide semiconductor electrode comprising titanium oxide, e.g. TiO2
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
  • H05B33/00—Electroluminescent light sources
  • H05B33/12—Light sources with substantially two-dimensional [2D] radiating surfaces
  • H05B33/26—Light sources with substantially two-dimensional [2D] radiating surfaces characterised by the composition or arrangement of the conductive material used as an electrode
  • H05B33/28—Light sources with substantially two-dimensional [2D] radiating surfaces characterised by the composition or arrangement of the conductive material used as an electrode of translucent electrodes
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
  • H10F71/00—Manufacture or treatment of devices covered by this subclass
  • H10F71/138—Manufacture of transparent electrodes, e.g. transparent conductive oxides [TCO] or indium tin oxide [ITO] electrodes
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
  • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
  • H10H20/80—Constructional details
  • H10H20/83—Electrodes
  • H10H20/832—Electrodes characterised by their material
  • H10H20/833—Transparent materials
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
  • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
  • H10H20/80—Constructional details
  • H10H20/83—Electrodes
  • H10H20/832—Electrodes characterised by their material
  • H10H20/835—Reflective materials
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K30/00—Organic devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation
  • H10K30/80—Constructional details
  • H10K30/81—Electrodes
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K30/00—Organic devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation
  • H10K30/80—Constructional details
  • H10K30/81—Electrodes
  • H10K30/82—Transparent electrodes, e.g. indium tin oxide [ITO] electrodes
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K50/00—Organic light-emitting devices
  • H10K50/80—Constructional details
  • H10K50/805—Electrodes
  • H10K50/81—Anodes
  • H10K50/816—Multilayers, e.g. transparent multilayers
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
  • H10K50/00—Organic light-emitting devices
  • H10K50/80—Constructional details
  • H10K50/805—Electrodes
  • H10K50/82—Cathodes
  • H10K50/828—Transparent cathodes, e.g. comprising thin metal layers
• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21K—HANDLING OF PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
  • G21K2201/00—Arrangements for handling radiation or particles
  • G21K2201/06—Arrangements for handling radiation or particles using diffractive, refractive or reflecting elements
  • G21K2201/061—Arrangements for handling radiation or particles using diffractive, refractive or reflecting elements characterised by a multilayer structure
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J2211/00—Plasma display panels with alternate current induction of the discharge, e.g. AC-PDPs
  • H01J2211/20—Constructional details
  • H01J2211/22—Electrodes
  • H01J2211/225—Material of electrodes
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E10/00—Energy generation through renewable energy sources
  • Y02E10/50—Photovoltaic [PV] energy
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E10/00—Energy generation through renewable energy sources
  • Y02E10/50—Photovoltaic [PV] energy
  • Y02E10/542—Dye sensitized solar cells
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E10/00—Energy generation through renewable energy sources
  • Y02E10/50—Photovoltaic [PV] energy
  • Y02E10/549—Organic PV cells

Definitions

• Figure 7 represents the visible optical transparency (VOT) in the visible wavelengths against electrical sheet resistance of Cu, Cu+Ni1 , Cu+Ti1 and Cu+Ti3_0 2 treated.
• an electrode which comprises a substrate and a layered structure comprising an electrically conductive film (2) in contact with at least one ultra thin metal film, (3) wherein the two films are of different materials and
• an ultra thin metal film presents a thickness of less than or equal to 6 nm and can be obtained as explained below.
• electrically conducting films of a metal with a thickness typically in the range of 3 to 20 nm are useful for transparent electrodes.
• optically transparent refers to a transmission of more than 40% of the light in the wavelength range of interest which depends on the application. For example for visible OLEDs the range is between 375 and 700 nm, for UV photodetectors between 100 and 400 nm, for photovoltaic cells between 350 and 800 nm, for mid-infrared detectors between 3 and 25 ⁇ , etc.
• Cu is an inexpensive material with excellent electrical and optical properties which is already widely used in microelectronics.
• Cu is known to be subjected to oxidation and corrosion, which alter significantly its electrical and optical properties. This disadvantage is solved by the use of an ultra thin metal film to cover the Cu electrically conductive film.
• the ultra thin metal film in this case protects the Ag.
• Ag is inert and presents thus the further advantage that it does not affect properties of other materials present in the optoelectronic device, such as an active material.
• Ni for instance as an ultra thin metal film can improve the work function of the electrode with Ag and protect it.
• Au as the material for the electrically conductive film is stable and inert and does not generate any problems to active materials.
• the ultra thin metal film in contact with the Au film has the advantage of adapting the work function of the corresponding electrode and optoelectronic device.
• Al as the material for the electrically conductive film is similar to Ag and the ultrathin metal film in this case has the properties of protecting it or tuning its work function or both.
• the electrically conductive film (2) of the bilayered-structure is in contact with the substrate (1 ).
• the UTMF (3) is in contact with the substrate.
• the electrode of the invention can besides present among others the structures illustrated in Figures 3 to 6.
• the electrically conductive film is deposited onto the substrate of the electrode of the invention.
• the film is deposited onto the UTMF film
• the substrate of the electrode of the invention can be of any suitable dielectric material on which the bilayered structure is grown upon, such as glass, a semiconductor, an inorganic crystal, a rigid or flexible plastic material.
• Illustrative examples are silica (Si0 2 ), borosilicate (BK7), silicon (Si), lithium niobate (LiNb0 3 ), polyethylen naphthalate (PEN), polyethelene terephthalate (PET), among others.
• Said substrate can be part of an optoelectronic device structure, e.g. an active semiconductor or organic layer.
• the starting surface roughness of the layer on which a film is deposited should preferably be below the thickness of the film to be deposited; otherwise said electrically conductive film could be discontinuous and thus non-conductive. It is possible to deposit continuous electrically conductive films on surfaces with a roughness equal to or larger than the thickness of the film when such roughness refers to surface peak-to-valley distances much larger than the film thickness.
• the continuity is mandatory for the electrical conductive film while it is preferable, though not necessary, for the ultrathin metal film.
• the electrode comprises at least a further film (4) in contact with a UTMF film wherein said film is selected from the group of
• the oxide film can be obtained by sputtering, evaporation and other deposition techniques known to a person skilled in the art.
• the transparency and electrical sheet resistance of a Cu electrically conductive film are in the range for practical application (> 70%, ⁇ 50 ⁇ /sq).
• a Cu film of thickness between 4 and 10 nm and a 1 - 3 nm thick Ni UTMF. More advantageously the Cu film is between 6.5-6.6 nm.
• Said Ni UTMF can have been annealed (for instance 1 hour at 120 5 C), showing extremely high heat-resistance properties, which can stabilize the Cu film, maintain the square resistance and slightly improve the optical transparency. These electrodes are useful in harsh environment device applications.
• the electrode is a transparent electrode having a Cu electrically conductive film, a FMF, and at least an oxide film in the range of 5 to 200 nm.
• the visible optical transparency is an average value over the 375 to 700 nm range where the substrate contribution has been subtracted.
• the first and the second numbers are respectively the Cu and the UTMF thicknesses.
• Table 1 electrical and optical properties of as deposited and thermally treated films in ambient atmosphere As deposited After annealing at 120 5 C for 1 h
• T is the average optical visible transparency from 375 to 700 nm and R s is the square resistance.
• Figure 1 1 shows the figure of merit for the different sets of samples.
• the Cu+Ti3_02 treated samples present a peak value of ⁇ ⁇ ⁇ equal to 2.5 x 10 ⁇ 3 ⁇ "1 .
• the best figure of merit is obtained for Cu thickness between 5.5 and 6.5 nm which indicates that Cu becomes continuous in this range.
• the percolation threshold was estimated by plotting R s t 3 versus t (where t stands for the film thickness) 15 for the different sets of samples (inset of fig. 1 1 ).
• the percolation thresholds for all the sets are found to be between 5.5 nm and 6.5 nm, which reassert the inventor's prediction above.
• One sample was deposited for each set with fixed Cu thickness of 6.5 nm which is defined from percolation thickness (inset of fig. 1 1 ).
• RMS roughness for all the four samples measured by AFM shows peak-to-valley values much less than the films thickness.
• Figure 12 shows the transparency spectrum for all these samples.
• the different optical transmission behaviours in visible-light region can be explained in terms of reflection and absorption.
• Figure 14 compares the transparency of 0 2 treated Cu 6.5nm+Ti 5nm as deposited and after annealing for 60 min at 120 5 C in atmosphere ambient. From the graph it is evident that the annealing treatment does not change significantly the transparency of the films in the visible range. The square resistance of the films increased only slightly with the annealing (from 15.9 to 19.8 ⁇ /D). It is thus clear that 5 nm oxidised Ti FMF practically protects the underlying Cu from oxidation in harsh environment.
• Table 2 electrical and optical properties of 0 2 treated films before and after thermal treatment (annealing) in ambient atmosphere
• Electrodes of the present invention show average transparency as high as 75% in visible-light range and square resistance as low as 20 ⁇ /D .
• the figure of merit ⁇ ⁇ ⁇ of Cu based bilayered electrodes is found to be rather better than SWNT and graphene films.
• the Cu+Ni1 and 0 2 treated Cu+Ti5 samples show excellent stability even after a heat treatment in oven for 60 min at 120 5 C in atmosphere ambient.
• the inventors have achieved exploiting the electrical and optical properties of materials, in particular Cu, or other similar electrically conductive materials, without the shortcomings of existing electrodes of the state of the art.
• the electrodes of the invention are stable and transparent conductive electrodes which find many applications due to their simple and low cost structure and method of fabrication and their intrinsic technical characteristics.
• the stability of the electrodes is of outmost importance to maintain the performance of the devices over time, in particular under demanding and changing environmental conditions.
• the transparent electrodes of the invention can thus be used in a wide variety of devices.
• the invention relates to an opto-electronic device which comprises at least an electrode as above defined.
• Said device can be a light emitting diode (LED), an organic light emitting diode (OLED), a display, a photovoltaic cell, an optical detector, an optical modulator, an electro-chromic device, an E-paper, a touch-screen, an electromagnetic shielding layer, and a transparent or smart (e.g. energy saving, defrosting) window, etc.
• Electrodes according to the invention corresponding to the embodiment illustrated in Figure 1 were obtained.
• Optically double sided polished UV fused silica substrates were first cleaned each with acetone and ethanol for 10 minutes in ultrasonic bath and then dried with nitrogen gun.
• the clean substrates were then loaded in the main chamber of the sputtering system (Ajaint Orion 3 DC) with pressure levels down to the order of 1 .33x10 "6 Pa (10 ⁇ 8 Torr)
• the sputtering was performed at room temperature in a pure argon atmosphere of 0.226 Pa (2 mTorr) and 100 W DC power.
• the target has the purity levels of 99.99%.
• Prior to the deposition the substrate was again cleaned with oxygen plasma with base pressure of 1 .06 Pa (8mTorr) and 40 W RF power for 15 minutes.
• Cu and Ni were deposited using DC sputtering while Ti was fabricated with RF sputtering.
• the thicknesses were monitored by MCM-160 quartz crystal.
• the deposition rates were determined as 1 .5 A/s for Cu, 0.573 A/s for Ni and 0.083 A/s for Ti.
• the electrically conductive film was Cu with thicknesses between 3-10 nm and the functional metal film was Ni or Ti with thicknesses between 1 nm and 5 nm.
• four different sets of varied Cu thickness were fabricated, viz.
• the 3 and 5 nm Ti on Cu were then in situ oxidized for 15 minutes using 0 2 plasma with working pressure of 8mT and 40 W RF power (hereafter, abbreviated as 0 2 Treated).
• Perkin Elmer lambda 950 spectrometer was used for the transmission spectra measurements while Cascade Microtech 44/7 S 2749 four-point probe system and Keithley 2001 multimeter for square resistance measurements.
• the fabricated films were characterized by Atomic Force Microscopy (AFM) with a digital instrument D3100 AFM and associated software WsXM.
• AFM Atomic Force Microscopy

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• 2009
  • 2009-11-03 EP EP09382238A patent/EP2317562A1/en not_active Withdrawn
• 2010
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