US20050072679A1 - Germanium and germanium alloy nanoparticle and method for producing the same - Google Patents
Germanium and germanium alloy nanoparticle and method for producing the same Download PDFInfo
- Publication number
- US20050072679A1 US20050072679A1 US10/849,536 US84953604A US2005072679A1 US 20050072679 A1 US20050072679 A1 US 20050072679A1 US 84953604 A US84953604 A US 84953604A US 2005072679 A1 US2005072679 A1 US 2005072679A1
- Authority
- US
- United States
- Prior art keywords
- germanium
- etchant solution
- nanoparticles
- germanium alloy
- alloy electrode
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- C25C5/00—Electrolytic production, recovery or refining of metal powders or porous metal masses
- C25C5/02—Electrolytic production, recovery or refining of metal powders or porous metal masses from solutions
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/02—Silicon
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25C—PROCESSES FOR THE ELECTROLYTIC PRODUCTION, RECOVERY OR REFINING OF METALS; APPARATUS THEREFOR
- C25C1/00—Electrolytic production, recovery or refining of metals by electrolysis of solutions
- C25C1/22—Electrolytic production, recovery or refining of metals by electrolysis of solutions of metals not provided for in groups C25C1/02 - C25C1/20
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/30—Structure or shape of the active region; Materials used for the active region
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B41/00—Obtaining germanium
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/14—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range characterised by the material used as the active medium
- H01S3/16—Solid materials
- H01S3/163—Solid materials characterised by a crystal matrix
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/04—Processes or apparatus for excitation, e.g. pumping, e.g. by electron beams
- H01S5/041—Optical pumping
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/30—Structure or shape of the active region; Materials used for the active region
- H01S5/3027—IV compounds
- H01S5/3031—Si
Definitions
- a field of the invention is nanomaterials.
- Silicon nanoparticles of ⁇ 1 nm diameter have shown stimulated emissions.
- Bulk silicon is an optically dull indirect bandgap material, having a 1.1 eV indirect bandgap, and a 3.2 eV direct bandgap.
- a 1 nm silicon nanoparticle effectively creates a new wideband direct gap material, with an energy gap of 3.55 eV, and highly efficient optical activity.
- a 1 nm silicon nanoparticle indirect band gap of 1.1 eV corresponds to a wavelength of 1.1 ⁇ m, which is in the infrared region. Our previous work with 1 nm silicon nanoparticles has shown moderate emission activity in the infrared region.
- the uniformly dimensioned 1 nm silicon nanoparticles (having about 1 part in one thousand or less of greater dimensions) produced in earlier work have characteristic blue emissions. See, e.g., Akcakir et al, “Detection of luminescent single ultrasmall silicon nanoparticles using fluctuation correlation spectroscopy”, Appl. Phys. Lett. 76 (14), p. 1857 (Apr. 3, 2000). Silicon nanoparticles have also been synthesized with H— or O-termination, or functionalized with N—, or C-linkages.
- Optical interconnects have many uses.
- An example use is for high-speed data communications between servers, either at the cabinet-to-cabinet or board-to-board levels.
- Another use is for chip-level interconnects.
- Current technology utilizes III-V systems, such as GaAs or InP—InGaGa PiN.
- Group IV materials hold special interest due to their benign nature and because of fabrication advantages.
- Silicon based detectors for example, may be fabricated in a conventional silicon CMOS process, which typically can be implemented at lower cost than the Group III-V fabrication processes.
- Nanoparticle-based photodetectors also referred to as quantum dot photodetectors, present an opportunity for enhancing the photon-to-current conversion efficiency compared to bulk devices to a degree that can alleviate or eliminate the need for amplification circuitry used in conventional systems to make use of the small photocurrent created in conventional bulk silicon detector devices.
- Systems based on films of Si, Ge, and GeSi nanoparticles or quantum dots have been recently demonstrated, but with moderate efficiency.
- Ge-based photodetector utilizing films consisting of large quantum substructures (50 nm) have respective responses of 130, 0.16, and 0.08 mA/W under the wavelengths of 820, 1300, and 1550 nm.
- an electrochemical etching of crystalline germanium or a germanium alloy produces well-segregated chromatic clusters of nanoparticles. Distinct strong bands appear in the photoluminescence spectra under 350 nm excitation with the lowest peaks in wavelength identified to be at 430, 480, and 580 and 680-1100 nm.
- the material may be dispersed into a discrete set of luminescent nanoparticles of 1-3 nm in diameter, which may be prepared into colloids and reconstituted into films, crystals, etc.
- FIGS. 1A and 1B show the photoluminescence spectra of the etched Ge wafer taken from different regions of an experimental sample under 365 nm excitation;
- FIG. 2 shows the photoluminescence of an experimental GE sample in the infrared taken under an excitation source of 365 nm;
- FIG. 3 shows the FTIR spectrum of an experimental Ge sample.
- the invention concerns germanium and germanium alloy nanoparticles and methods for making the same. Infrared emissions from nanaparticles command a special interest in myriad applications. Highly-efficient nanomaterial-based photodetectors or phototransistors in the infrared can form the basis for chip-to-chip and board-to-board optical interconnects. In relation to bulk silicon, bulk germanium reduces the indirect band gap (0.66 vs. 1.1 eV), and the direct band gaps (0.9 vs. 3.2 eV), and one use of germanium nanoparticles of the invention is to extend the photosensitive response into the infrared.
- etching processes of crystalline germanium or a germanium alloy in a chemical etchant solution e.g., HF/H 2 O 2 /H 2 O
- a chemical etchant solution e.g., HF/H 2 O 2 /H 2 O
- Sensitive Si/Ge nanoparticle material-based devices can therefore cover a wide range of wavelengths from near UV to infrared.
- a particularly useful application of efficient response in the infrared band is use in infrared biological imaging applications.
- a method for creating clusters of the nanoparticles of an embodiment of the invention is a bipolar electrochemical treatment which involves insertion of bulk germanium or germanium alloy, e.g. a wafer, into a chemical etch solution, in the presence of an external current.
- the germanium serves as an electrode in an electrochemical etching process.
- Another electrode also contacts the chemical etch bath.
- current is reversed.
- a gradual advance of the wafer into the bath may be used to increase the area of etching.
- An example rate is about one millimeter per minute.
- Current is reversed, in this case, as a gradual retreat of the wafer is conducted.
- current reversal may be executed after a lift of the wafer to its original height to begin a second period of gradual advance of the wafer.
- a different etchant solution i.e., an aqueous HCl/methanol electrolyte bath is used.
- the etching process creates a layer of uniformly dimensioned Ge nanoparticles on the surface of the bulk germanium.
- the Ge electrode with Ge nanoparticles formed on its surface is separated from the etchant solution. The Ge with the nanoparticle surface may then be rinsed to remove any etchant solution.
- the particles may be removed from the bulk material by an agitation process, e.g, shaking, banging, scraping or ultrasonic agitation, the latter of which is preferred.
- an agitation process e.g, shaking, banging, scraping or ultrasonic agitation, the latter of which is preferred.
- any method which separates the nanoparticles from the etched bulk Ge or Ge alloy surface is suitable, but a solvent with breaking force supplied by ultrasound waves is preferred.
- Example solvents include acetone, alcohol, water, and other organic solvents.
- various methods may be employed to form nanoparticles into colloids, crystals, films and other desirable forms.
- the particles may also be coated or doped. The coating and doping processes are similar to those described in U.S. Pat. No.
- H-terminated germanium particles may be functionalized with alkynes. For example, refluxing in a 20% 1-dodecene solution in mesitylene (v/v) for several hours results in the incorporation of surface-bound dodecyl moieties. It is a thermally induced hydrogermylation reaction.
- the bulk germanium is replaced with an alloy of silicon-germanium.
- Electrochemical etching as discussed above is applied to disperse the alloy into nanoparticles.
- Alloys may be produced by ion implantation or molecular beam epitaxy procedures.
- An example embodiment uses Germanium-silicon wafers of 20-80 (Ge-silicon) composition. For this ratio, a nanoparticle of 1 nm in diameter may have Si 24 Ge 5 configuration ( 24 silicon atoms and 5 Ge atoms), or we can use 80-20 (Ge-silicon) composition which gives Ge 24 Si 5 .(5 silicon atoms and 24 Ge atoms).
- the proportion of Ge to the alloy element permits tuning the composition, which allows tuning of the wavelength response of alloyed or doped nanoparticles. Our theoretical simulations show that several high quality Si/Ge nanoparticles configurations are possible.
- the wafer was etched for 5 minutes at anodizing current of 180 mA, providing a density of 350 mA/cm 2 .
- anodizing current 180 mA
- the polarity of the electrodes was reversed to perform a cathodization etch step for 2 minutes.
- FIGS. 1A and 1B give the spectra taken.
- the luminescence band peaks at 425 nm.
- the sharp rise on the blue edge of the band is caused by the cutoff filter.
- the emission band peaks at 490 nm. In many cases there is a hint of a yellow shoulder at 580 mm.
- a fiber optic spectrometer which includes optical fibers to transport the excitation and to extract the emission.
- a holographic grating that is a polymer replica of a master grating. It is a near infrared grating with groove density of 600/mm with a blaze angle of 1 ⁇ m and with best efficiency in the range 0.65-1.1 ⁇ m.
- Another channel utilized a UV-VIS holographic grating, with groove density of 600/mm with a blaze wavelength of 0.4 ⁇ m and with best efficiency in the range 0.25-0.80 ⁇ m.
- the near infrared (NIR) fiber has nearly an attenuation of 50 db/km. In the region of interest 900-1000 nm the transmission is ⁇ 90 percent.
- FIG. 2 shows the spectrum in the infrared, taken with an excitation source of 365 nm.
- the line shape of the infrared band is asymmetric rising sharply at 680 nm and dropping slowly well into the infrared at ⁇ 1100 nm. Correcting for the efficiency of the infrared detector, and averaging over measurements shows that the infrared is two fold stronger than the visible emission.
- Photoluminescence may be explained in terms of quantum confinement in—nanostructures.
- the lattice constants of Si and Ge are comparable, being 5 percent larger in Ge.
- a spherical cut of 1 nm diameter in bulk Ge gives Ge 29 , a cluster consisting of 29 germanium atoms.
- a similar cut in Si gives also a cluster of 29 silicon atoms (Si 29 ).
- a method for producing a discrete family of silicon nanoparticles includes particles of diameters 1, 1.67, 2.15, 2.85, and 3.7 nm. See, e.g., Belomoin et al. “Observation of a magic discrete family of ultrabright Si nanoparticles,” Appl. Phys. Lett.
- Ge nanoparticles Based upon the size difference between Si and Ge, Ge nanoparticles would have corresponding sizes of 1, 1.75, 2.25, 3.0, and 3.9 nm.
- Si and Ge Significant differences between Si and Ge exist in the infrared part of the spectrum. Silicon nanoparticles of different sizes give band edge luminescence at 1160-1300 nm with an efficiency of 6% of the visible emission. Germanium nanoparticles give photoluminescence in the range 680-1100 nm with an efficiency that is comparable or larger than the visible emission. Germanium is also expected to produce luminescence in the range 1,500 to 3,000 nm.
- the extension of strong emission into the infrared in Ge is due to the reduced bandgaps in bulk Ge compared to Si (0.66 vs. 1.1 eV indirect), and (0.9 vs. 3.2 eV direct).
- the method of the invention produces Ge and Ge-alloy nanoparticles having a size in the range of ⁇ 1-3 nm.
- aqueous HCl/methanol electrolyte bath with a small fraction of H 2 O 2 .
- a Teflon chamber cylinder is sealed on the bottom by the wafer.
- a metal plate makes electrical contact with the backside of the wafer.
- the cylinder is filled with the etching solution.
- the etchant is a 1:1 mixture of HCl, and methanol.
- a platinum wire electrode is immersed in the etchant normal to the substrate at a certain height (2 cm for example) above it.
- the wafer With the germanium substrate acting as the anode, and the platinum wire acting as a cathode, the wafer is anodized for 5 minutes at an appropriate anodizing current density for etching, e.g., ⁇ 230 mA/cm 2 .
- an appropriate anodizing current density for etching e.g., ⁇ 230 mA/cm 2 .
- the polarity of the electrodes is reversed to perform a cathodization step for 2 minutes.
- the etchant is then removed, and the wafer is rinsed with water followed by an acetone rinse and a drying period. Similar spectra of particle clusters are observed, but the distribution is now skewed towards the orange/red sizes.
Abstract
Description
- This application is a continuation-in-part of co-pending application serial number 990,250, filed Nov. 21, 2001, published on Jul. 13, 2002, as publication number 20020070121 entitled FAMILY OF DISCRETELY SIZED NANOPARTICLES AND METHOD FOR PRODUCING THE SAME, which was a continuation in part of Nayfeh et al. U.S. patent application Ser. No. 09/426,389, entitled METHOD FOR PRODUCING SILICON NANOPARTICLES, filed Oct. 22, 1999, and now U.S. Pat. No. 6,585,947. Priority from both applications is claimed under 35 U.S.C. § 120.
- This invention was made with Government assistance under contract number 1529304 awarded by the National Science Foundation. The Government has certain rights in this invention.
- A field of the invention is nanomaterials.
- Silicon nanoparticles of ˜1 nm diameter have shown stimulated emissions. Bulk silicon is an optically dull indirect bandgap material, having a 1.1 eV indirect bandgap, and a 3.2 eV direct bandgap. A 1 nm silicon nanoparticle effectively creates a new wideband direct gap material, with an energy gap of 3.55 eV, and highly efficient optical activity. A 1 nm silicon nanoparticle indirect band gap of 1.1 eV corresponds to a wavelength of 1.1 μm, which is in the infrared region. Our previous work with 1 nm silicon nanoparticles has shown moderate emission activity in the infrared region. The uniformly dimensioned 1 nm silicon nanoparticles (having about 1 part in one thousand or less of greater dimensions) produced in earlier work have characteristic blue emissions. See, e.g., Akcakir et al, “Detection of luminescent single ultrasmall silicon nanoparticles using fluctuation correlation spectroscopy”, Appl. Phys. Lett. 76 (14), p. 1857 (Apr. 3, 2000). Silicon nanoparticles have also been synthesized with H— or O-termination, or functionalized with N—, or C-linkages. Previous work also produced a family of uniformly dimensioned nanoparticles with distinct particle sizes in the 1-3 nm range, which fluoresce spectacularly, and an additional particle that emits in the infrared band. The family includes 1 (blue emitting), 1.67 (green emitting), 2.15 (yellow emitting), 2.9 (red emitting) and 3.7 nm (infrared emitting). See, G. Belomoin et al. “Observation of a magic discrete family of ultrabright Si nanoparticles,” Appl. Phys. Lett. 80(5), p 841 (Feb. 4, 2002); and United States Published Patent Application 20020070121 to Nayfeh et al.
- Optical interconnects have many uses. An example use is for high-speed data communications between servers, either at the cabinet-to-cabinet or board-to-board levels. Another use is for chip-level interconnects. Current technology utilizes III-V systems, such as GaAs or InP—InGaGa PiN. Group IV materials hold special interest due to their benign nature and because of fabrication advantages. Silicon based detectors, for example, may be fabricated in a conventional silicon CMOS process, which typically can be implemented at lower cost than the Group III-V fabrication processes.
- Conventional optical detectors made on compound semiconductor substrates are bonded with a bulk silicon die for a multi-chip solution that is relatively costly. However, due to the large absorption length (20 μm) of silicon at 820 nm and the forbidden absorption at 1300 and 1550 nm, bulk silicon-based photodetectors have limited detection efficiency and wavelength range. Germanium or gallium arsenide-based systems offer better absorption and sensitivity at 1300 and 1550 nm over bulk silicon.
- Nanoparticle-based photodetectors, also referred to as quantum dot photodetectors, present an opportunity for enhancing the photon-to-current conversion efficiency compared to bulk devices to a degree that can alleviate or eliminate the need for amplification circuitry used in conventional systems to make use of the small photocurrent created in conventional bulk silicon detector devices. Systems based on films of Si, Ge, and GeSi nanoparticles or quantum dots have been recently demonstrated, but with moderate efficiency. For instance, Ge-based photodetector utilizing films consisting of large quantum substructures (50 nm) have respective responses of 130, 0.16, and 0.08 mA/W under the wavelengths of 820, 1300, and 1550 nm. See, e.g., “High efficiency 820 nm MOS Ge quantum dot photodetectors for short-reach integrated optical receivers with 1300 and 1550 nm sensitivity,” B. C. Hsu, et al. IEDM, 91 (2002)(IEEE publication). These levels of current response are below those that would provide a simple integration into optoelectronic devices for short reach optoelectronic communications. Higher performance, particularly at 820 nm, would make it feasible to integrate optoelectronic devices into silicon chips for short-reach optical communications.
- In the invention, an electrochemical etching of crystalline germanium or a germanium alloy produces well-segregated chromatic clusters of nanoparticles. Distinct strong bands appear in the photoluminescence spectra under 350 nm excitation with the lowest peaks in wavelength identified to be at 430, 480, and 580 and 680-1100 nm. The material may be dispersed into a discrete set of luminescent nanoparticles of 1-3 nm in diameter, which may be prepared into colloids and reconstituted into films, crystals, etc.
-
FIGS. 1A and 1B show the photoluminescence spectra of the etched Ge wafer taken from different regions of an experimental sample under 365 nm excitation; -
FIG. 2 shows the photoluminescence of an experimental GE sample in the infrared taken under an excitation source of 365 nm; and -
FIG. 3 shows the FTIR spectrum of an experimental Ge sample. - The invention concerns germanium and germanium alloy nanoparticles and methods for making the same. Infrared emissions from nanaparticles command a special interest in myriad applications. Highly-efficient nanomaterial-based photodetectors or phototransistors in the infrared can form the basis for chip-to-chip and board-to-board optical interconnects. In relation to bulk silicon, bulk germanium reduces the indirect band gap (0.66 vs. 1.1 eV), and the direct band gaps (0.9 vs. 3.2 eV), and one use of germanium nanoparticles of the invention is to extend the photosensitive response into the infrared.
- In the invention, we employ electrochemical etching processes of crystalline germanium or a germanium alloy in a chemical etchant solution, e.g., HF/H2O2/H2O to produce, well-segregated chromatic clusters of nanoparticle material, which under 365 nm UV excitation, exhibit ultrabright blue, green, and yellow/orange photoluminescence, as well as very efficient infrared radiation. Sensitive Si/Ge nanoparticle material-based devices, can therefore cover a wide range of wavelengths from near UV to infrared. A particularly useful application of efficient response in the infrared band is use in infrared biological imaging applications.
- A method for creating clusters of the nanoparticles of an embodiment of the invention is a bipolar electrochemical treatment which involves insertion of bulk germanium or germanium alloy, e.g. a wafer, into a chemical etch solution, in the presence of an external current. The germanium serves as an electrode in an electrochemical etching process. Another electrode also contacts the chemical etch bath. During the etching, current is reversed. A gradual advance of the wafer into the bath may be used to increase the area of etching. An example rate is about one millimeter per minute. Current is reversed, in this case, as a gradual retreat of the wafer is conducted. Also, current reversal may be executed after a lift of the wafer to its original height to begin a second period of gradual advance of the wafer.
- In a preferred embodiment of the invention, we employ electrochemical etching processes of crystalline germanium in an etching solution of HF/H2O2/H2O and methanol. In another embodiment, a different etchant solution, i.e., an aqueous HCl/methanol electrolyte bath is used. The etching process creates a layer of uniformly dimensioned Ge nanoparticles on the surface of the bulk germanium. After etching, the Ge electrode with Ge nanoparticles formed on its surface is separated from the etchant solution. The Ge with the nanoparticle surface may then be rinsed to remove any etchant solution. The particles may be removed from the bulk material by an agitation process, e.g, shaking, banging, scraping or ultrasonic agitation, the latter of which is preferred. Generally, any method which separates the nanoparticles from the etched bulk Ge or Ge alloy surface is suitable, but a solvent with breaking force supplied by ultrasound waves is preferred. In the ultrasound bath, one can use a variety of solvents since the particles are hydrogen passivated Example solvents include acetone, alcohol, water, and other organic solvents. Once separated, various methods may be employed to form nanoparticles into colloids, crystals, films and other desirable forms. The particles may also be coated or doped. The coating and doping processes are similar to those described in U.S. Pat. No. 6,585,947 for the silicon nanoparticles, but the specific protocols used to coat may differ somewhat due to taking into account the different chemistry of Ge. H-terminated germanium particles may be functionalized with alkynes. For example, refluxing in a 20% 1-dodecene solution in mesitylene (v/v) for several hours results in the incorporation of surface-bound dodecyl moieties. It is a thermally induced hydrogermylation reaction.
- In another embodiment of the invention, the bulk germanium is replaced with an alloy of silicon-germanium. Electrochemical etching as discussed above is applied to disperse the alloy into nanoparticles. Alloys may be produced by ion implantation or molecular beam epitaxy procedures. An example embodiment uses Germanium-silicon wafers of 20-80 (Ge-silicon) composition. For this ratio, a nanoparticle of 1 nm in diameter may have Si24Ge5 configuration (24 silicon atoms and 5 Ge atoms), or we can use 80-20 (Ge-silicon) composition which gives Ge24Si5.(5 silicon atoms and 24 Ge atoms). The proportion of Ge to the alloy element permits tuning the composition, which allows tuning of the wavelength response of alloyed or doped nanoparticles. Our theoretical simulations show that several high quality Si/Ge nanoparticles configurations are possible.
- We have conducted experiments to demonstrate the method of the invention. In an experiment, we prepared samples using an aqueous HF/methanol electrolyte bath that incorporates hydrogen peroxide (H2O2). The germanium samples used were (100) oriented, 1-10 ohm-cm resistivity, p-type boron doped Ge wafers. Moreover, HF terminates Ge with hydrogen while the highly oxidative peroxide cleans the wafer from organic-based impurities, resulting in high-quality nanostructures. The example etchant in the experiments was a mixture of 0.5 mL, 0.45 mL, and 0.4 mL of HF, H2O2, and methanol, i.e., in a near 1:1:1 volume ratio. The wafer was etched for 5 minutes at anodizing current of 180 mA, providing a density of 350 mA/cm2. At the end of anodization, the polarity of the electrodes was reversed to perform a cathodization etch step for 2 minutes.
- In the experiments, well-segregated chromatic clusters were produced, which under 365 nm UV excitation, exhibit ultrabright blue, green, and yellow/orange photoluminescence, as well as very efficient infrared radiation. Both HF and H2O are reactive with Ge oxide, thus the incorporation of the highly oxidative peroxide enhances the etching rate, producing much smaller nanostructures. The production of spatially resolved chromatic clusters is consistent with size dependent quantum confinement of radiative recombination in Ge nano structures.
- We took photoluminescence images using radiation from a Hg lamp, normally incident on the substrate. At the target, the power, 1-15 mW, focuses to a spot ˜0.5 mm diameter, using an objective of 0.6 NA, giving an intensity of 0.13-2 W/cm2. Luminescence is detected in the backward direction and recorded by an RGB filter/prism based dispersive charge coupled device (3CCD). Special cutoff filters filter scattering at the incident wavelength and the background is subtracted. Under 365 nm excitation, we observed blue, green, and yellow/orange luminescent clusters.
- We can prepare blue dominated samples at higher etching current conditions. These may be attributed to clusters of 1 nm Ge particles. Samples prepared under the higher current conductions, when excited under 365 nm excitation, show luminescence dominated by blue luminescent clusters with very little of the other colors.
- The spectral distribution was analyzed with an optical multichannel analyzer with a prism dispersive element.
FIGS. 1A and 1B give the spectra taken. When the beam is parked on blue clusters, the luminescence band peaks at 425 nm. The sharp rise on the blue edge of the band is caused by the cutoff filter. When the beam is parked on green/yellow spots, the emission band peaks at 490 nm. In many cases there is a hint of a yellow shoulder at 580 mm. - For detection of infrared activity, we used a fiber optic spectrometer, which includes optical fibers to transport the excitation and to extract the emission. We used a holographic grating that is a polymer replica of a master grating. It is a near infrared grating with groove density of 600/mm with a blaze angle of 1 μm and with best efficiency in the range 0.65-1.1 μm. Another channel utilized a UV-VIS holographic grating, with groove density of 600/mm with a blaze wavelength of 0.4 μm and with best efficiency in the range 0.25-0.80 μm. The near infrared (NIR) fiber has nearly an attenuation of 50 db/km. In the region of interest 900-1000 nm the transmission is ˜90 percent.
-
FIG. 2 shows the spectrum in the infrared, taken with an excitation source of 365 nm. There is a photoluminescence band in the infrared part of the spectrum (680-1100 nm). The line shape of the infrared band is asymmetric rising sharply at 680 nm and dropping slowly well into the infrared at ˜1100 nm. Correcting for the efficiency of the infrared detector, and averaging over measurements shows that the infrared is two fold stronger than the visible emission. - To determine if any oxidation occurs during the electrochemical etching process, we measured the infrared absorption in the range 500-4500 cm−1. The Fourier transform infrared (FTIR) data was taken in air using an ATI-Mattson Galaxy model GL-5020. The results shown in
FIG. 3 show absorption at 830-880 cm−1, which is due to bending modes of hydrogen bonded to the Ge crystallite surface. The germanium substrate signal has been subtracted from the data. The data also shows absorption at 550-600 cm−1 due to rocking hydrogen vibration modes. On the other hand we do not see an oxygen signal, which is expected to be in the region 900-1100 cm−1 region, indicating a high degree of hydrogen passivation. Thus, it is not likely that the emission from our samples is oxide-based. In fact the rate of oxide dissolution in aqueous solution is much faster than any common oxidation process. - Photoluminescence may be explained in terms of quantum confinement in—nanostructures. The lattice constants of Si and Ge are comparable, being 5 percent larger in Ge. Thus, a spherical cut of 1 nm diameter in bulk Ge gives Ge29, a cluster consisting of 29 germanium atoms. A similar cut in Si gives also a cluster of 29 silicon atoms (Si29). A method for producing a discrete family of silicon nanoparticles includes particles of
diameters 1, 1.67, 2.15, 2.85, and 3.7 nm. See, e.g., Belomoin et al. “Observation of a magic discrete family of ultrabright Si nanoparticles,” Appl. Phys. Lett. 80(5), p 841 (Feb. 4, 2002); and United States Published Patent Application 20020070121 to Nayfeh et al. Based upon the size difference between Si and Ge, Ge nanoparticles would have corresponding sizes of 1, 1.75, 2.25, 3.0, and 3.9 nm. - Significant differences between Si and Ge exist in the infrared part of the spectrum. Silicon nanoparticles of different sizes give band edge luminescence at 1160-1300 nm with an efficiency of 6% of the visible emission. Germanium nanoparticles give photoluminescence in the range 680-1100 nm with an efficiency that is comparable or larger than the visible emission. Germanium is also expected to produce luminescence in the range 1,500 to 3,000 nm. The extension of strong emission into the infrared in Ge is due to the reduced bandgaps in bulk Ge compared to Si (0.66 vs. 1.1 eV indirect), and (0.9 vs. 3.2 eV direct). Based on the activity in the visible, with observed emission bands whose peaks lie in the blue, green, and yellow appear to originate from the important substructure regime of 1-3 nm Ge nanoparticles. The method of the invention produces Ge and Ge-alloy nanoparticles having a size in the range of ˜1-3 nm.
- In another embodiment, we used an aqueous HCl/methanol electrolyte bath with a small fraction of H2O2. A Teflon chamber cylinder is sealed on the bottom by the wafer. A metal plate makes electrical contact with the backside of the wafer. The cylinder is filled with the etching solution. The etchant is a 1:1 mixture of HCl, and methanol. A platinum wire electrode is immersed in the etchant normal to the substrate at a certain height (2 cm for example) above it. With the germanium substrate acting as the anode, and the platinum wire acting as a cathode, the wafer is anodized for 5 minutes at an appropriate anodizing current density for etching, e.g., ˜230 mA/cm2. At the end of this anodization step, the polarity of the electrodes is reversed to perform a cathodization step for 2 minutes. The etchant is then removed, and the wafer is rinsed with water followed by an acetone rinse and a drying period. Similar spectra of particle clusters are observed, but the distribution is now skewed towards the orange/red sizes.
- In another embodiment, we find that we can enhance the formation of the nanoparticles and increase the yield by adding to the etchant a Ge salt solution, such as GeCl4. Moreover we can also enhance formation by adding to the etchant granular Ge, which is crushed Ge wafers.
- While specific embodiments of the present invention have been shown and described, it should be understood that other modifications, substitutions and alternatives are apparent to one of ordinary skill in the art. Such modifications, substitutions and alternatives can be made without departing from the spirit and scope of the invention, which should be determined from the appended claims.
- Various features of the invention are set forth in the appended claims.
Claims (28)
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/849,536 US20050072679A1 (en) | 1999-10-22 | 2004-05-19 | Germanium and germanium alloy nanoparticle and method for producing the same |
EP05785299A EP1756335A4 (en) | 2004-05-19 | 2005-05-16 | Germanium and germanium alloy nanoparticle and method for producing the same |
PCT/US2005/017063 WO2005123985A2 (en) | 1999-10-22 | 2005-05-16 | Germanium and germanium alloy nanoparticle and method for producing the same |
JP2007527339A JP2008504448A (en) | 2004-05-19 | 2005-05-16 | Germanium and germanium alloy nanoparticles and method for producing them |
CN 200580020236 CN101379222A (en) | 2004-05-19 | 2005-05-16 | Germanium and germanium alloy nanoparticle and method for producing the same |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/426,389 US6585947B1 (en) | 1999-10-22 | 1999-10-22 | Method for producing silicon nanoparticles |
US09/990,250 US6743406B2 (en) | 1999-10-22 | 2001-11-21 | Family of discretely sized silicon nanoparticles and method for producing the same |
US10/849,536 US20050072679A1 (en) | 1999-10-22 | 2004-05-19 | Germanium and germanium alloy nanoparticle and method for producing the same |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/990,250 Continuation-In-Part US6743406B2 (en) | 1999-10-22 | 2001-11-21 | Family of discretely sized silicon nanoparticles and method for producing the same |
Publications (1)
Publication Number | Publication Date |
---|---|
US20050072679A1 true US20050072679A1 (en) | 2005-04-07 |
Family
ID=35510348
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/849,536 Abandoned US20050072679A1 (en) | 1999-10-22 | 2004-05-19 | Germanium and germanium alloy nanoparticle and method for producing the same |
Country Status (2)
Country | Link |
---|---|
US (1) | US20050072679A1 (en) |
WO (1) | WO2005123985A2 (en) |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20060094189A1 (en) * | 2003-01-08 | 2006-05-04 | Thomas B. Haverstock, Haverstock & Owens Llp | Nanoparticles and method for making the same |
WO2007016080A2 (en) * | 2005-07-26 | 2007-02-08 | The Board Of Trustees Of The University Of Illinois | Silicon nanoparticle formation from silicon powder and hexacholorplatinic acid |
US20090090893A1 (en) * | 2007-10-04 | 2009-04-09 | Nayfeh Munir H | Nanosilicon-based room temperature paints and adhesive coatings |
US20090134038A1 (en) * | 2005-10-05 | 2009-05-28 | Tadeusz Chudoba | Method of Chemical Reactions Conduction and Chemical Reactor |
US20090308441A1 (en) * | 2005-11-10 | 2009-12-17 | Nayfeh Munir H | Silicon Nanoparticle Photovoltaic Devices |
WO2011140045A1 (en) * | 2010-05-03 | 2011-11-10 | Empire Technology Development Llc | A method and apparatus for forming particles and for recovering electrochemically reactive material |
US20110316145A1 (en) * | 2010-06-29 | 2011-12-29 | National Central University | Nano/micro-structure and fabrication method thereof |
WO2012010501A1 (en) * | 2010-07-19 | 2012-01-26 | Universiteit Leiden | Process to prepare metal nanoparticles or metal oxide nanoparticles |
US11827993B1 (en) | 2020-09-18 | 2023-11-28 | GRU Energy Lab Inc. | Methods of forming active materials for electrochemical cells using low-temperature electrochemical deposition |
Citations (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3324327A (en) * | 1965-04-23 | 1967-06-06 | Hughes Aircraft Co | Infrared camera tube having grid-type infrared sensitive target |
US4931692A (en) * | 1987-10-14 | 1990-06-05 | Canon Kabushiki Kaisha | Luminescing member, process for preparation thereof, and electroluminescent device employing same |
US5259918A (en) * | 1991-06-12 | 1993-11-09 | International Business Machines Corporation | Heteroepitaxial growth of germanium on silicon by UHV/CVD |
US5527386A (en) * | 1993-10-28 | 1996-06-18 | Manfred R. Kuehnle | Composite media with selectable radiation-transmission properties |
US5537000A (en) * | 1994-04-29 | 1996-07-16 | The Regents, University Of California | Electroluminescent devices formed using semiconductor nanocrystals as an electron transport media and method of making such electroluminescent devices |
US5561679A (en) * | 1995-04-10 | 1996-10-01 | Ontario Hydro | Radioluminescent semiconductor light source |
US5690807A (en) * | 1995-08-03 | 1997-11-25 | Massachusetts Institute Of Technology | Method for producing semiconductor particles |
US5714766A (en) * | 1995-09-29 | 1998-02-03 | International Business Machines Corporation | Nano-structure memory device |
US5747180A (en) * | 1995-05-19 | 1998-05-05 | University Of Notre Dame Du Lac | Electrochemical synthesis of quasi-periodic quantum dot and nanostructure arrays |
US5850064A (en) * | 1997-04-11 | 1998-12-15 | Starfire Electronics Development & Marketing, Ltd. | Method for photolytic liquid phase synthesis of silicon and germanium nanocrystalline materials |
US5932889A (en) * | 1994-11-22 | 1999-08-03 | Sanyo Electric Co., Ltd. | Semiconductor device with floating quantum box |
US5942748A (en) * | 1993-09-09 | 1999-08-24 | The United States Of America As Represented By The Secretary Of The Navy | Liquid level sensor and detector |
US6060743A (en) * | 1997-05-21 | 2000-05-09 | Kabushiki Kaisha Toshiba | Semiconductor memory device having multilayer group IV nanocrystal quantum dot floating gate and method of manufacturing the same |
US6326311B1 (en) * | 1998-03-30 | 2001-12-04 | Sharp Kabushiki Kaisha | Microstructure producing method capable of controlling growth position of minute particle or thin and semiconductor device employing the microstructure |
US20020020833A1 (en) * | 1999-07-19 | 2002-02-21 | Fan Zhang | Composition for chemical mechanical planarization of copper, tantalum and tantalum nitride |
US6361660B1 (en) * | 1997-07-31 | 2002-03-26 | Avery N. Goldstein | Photoelectrochemical device containing a quantum confined group IV semiconductor nanoparticle |
US6585947B1 (en) * | 1999-10-22 | 2003-07-01 | The Board Of Trustess Of The University Of Illinois | Method for producing silicon nanoparticles |
US6631022B1 (en) * | 1999-05-28 | 2003-10-07 | Sony Corporation | Optical device, a fabrication method thereof, a driving method thereof and a camera system |
US6743406B2 (en) * | 1999-10-22 | 2004-06-01 | The Board Of Trustees Of The University Of Illinois | Family of discretely sized silicon nanoparticles and method for producing the same |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2500360B2 (en) * | 1993-06-23 | 1996-05-29 | 大阪大学長 | Method for producing compound ultrafine particles |
-
2004
- 2004-05-19 US US10/849,536 patent/US20050072679A1/en not_active Abandoned
-
2005
- 2005-05-16 WO PCT/US2005/017063 patent/WO2005123985A2/en active Application Filing
Patent Citations (20)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3324327A (en) * | 1965-04-23 | 1967-06-06 | Hughes Aircraft Co | Infrared camera tube having grid-type infrared sensitive target |
US4931692A (en) * | 1987-10-14 | 1990-06-05 | Canon Kabushiki Kaisha | Luminescing member, process for preparation thereof, and electroluminescent device employing same |
US5259918A (en) * | 1991-06-12 | 1993-11-09 | International Business Machines Corporation | Heteroepitaxial growth of germanium on silicon by UHV/CVD |
US5942748A (en) * | 1993-09-09 | 1999-08-24 | The United States Of America As Represented By The Secretary Of The Navy | Liquid level sensor and detector |
US5527386A (en) * | 1993-10-28 | 1996-06-18 | Manfred R. Kuehnle | Composite media with selectable radiation-transmission properties |
US5537000A (en) * | 1994-04-29 | 1996-07-16 | The Regents, University Of California | Electroluminescent devices formed using semiconductor nanocrystals as an electron transport media and method of making such electroluminescent devices |
US5932889A (en) * | 1994-11-22 | 1999-08-03 | Sanyo Electric Co., Ltd. | Semiconductor device with floating quantum box |
US5561679A (en) * | 1995-04-10 | 1996-10-01 | Ontario Hydro | Radioluminescent semiconductor light source |
US5747180A (en) * | 1995-05-19 | 1998-05-05 | University Of Notre Dame Du Lac | Electrochemical synthesis of quasi-periodic quantum dot and nanostructure arrays |
US5690807A (en) * | 1995-08-03 | 1997-11-25 | Massachusetts Institute Of Technology | Method for producing semiconductor particles |
US5714766A (en) * | 1995-09-29 | 1998-02-03 | International Business Machines Corporation | Nano-structure memory device |
US5850064A (en) * | 1997-04-11 | 1998-12-15 | Starfire Electronics Development & Marketing, Ltd. | Method for photolytic liquid phase synthesis of silicon and germanium nanocrystalline materials |
US6060743A (en) * | 1997-05-21 | 2000-05-09 | Kabushiki Kaisha Toshiba | Semiconductor memory device having multilayer group IV nanocrystal quantum dot floating gate and method of manufacturing the same |
US6361660B1 (en) * | 1997-07-31 | 2002-03-26 | Avery N. Goldstein | Photoelectrochemical device containing a quantum confined group IV semiconductor nanoparticle |
US6326311B1 (en) * | 1998-03-30 | 2001-12-04 | Sharp Kabushiki Kaisha | Microstructure producing method capable of controlling growth position of minute particle or thin and semiconductor device employing the microstructure |
US6631022B1 (en) * | 1999-05-28 | 2003-10-07 | Sony Corporation | Optical device, a fabrication method thereof, a driving method thereof and a camera system |
US20020020833A1 (en) * | 1999-07-19 | 2002-02-21 | Fan Zhang | Composition for chemical mechanical planarization of copper, tantalum and tantalum nitride |
US6630433B2 (en) * | 1999-07-19 | 2003-10-07 | Honeywell International Inc. | Composition for chemical mechanical planarization of copper, tantalum and tantalum nitride |
US6585947B1 (en) * | 1999-10-22 | 2003-07-01 | The Board Of Trustess Of The University Of Illinois | Method for producing silicon nanoparticles |
US6743406B2 (en) * | 1999-10-22 | 2004-06-01 | The Board Of Trustees Of The University Of Illinois | Family of discretely sized silicon nanoparticles and method for producing the same |
Cited By (17)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7259100B2 (en) * | 2003-01-08 | 2007-08-21 | Kovio, Inc. | Nanoparticles and method for making the same |
US20060094189A1 (en) * | 2003-01-08 | 2006-05-04 | Thomas B. Haverstock, Haverstock & Owens Llp | Nanoparticles and method for making the same |
US7259101B2 (en) * | 2003-01-08 | 2007-08-21 | Kovio, Inc. | Nanoparticles and method for making the same |
US20100044344A1 (en) * | 2005-07-26 | 2010-02-25 | Nayfeh Munir H | Silicon Nanoparticle Formation From Silicon Powder and Hexacholorplatinic Acid |
WO2007016080A2 (en) * | 2005-07-26 | 2007-02-08 | The Board Of Trustees Of The University Of Illinois | Silicon nanoparticle formation from silicon powder and hexacholorplatinic acid |
WO2007016080A3 (en) * | 2005-07-26 | 2007-03-29 | Univ Illinois | Silicon nanoparticle formation from silicon powder and hexacholorplatinic acid |
US20090134038A1 (en) * | 2005-10-05 | 2009-05-28 | Tadeusz Chudoba | Method of Chemical Reactions Conduction and Chemical Reactor |
US9263600B2 (en) | 2005-11-10 | 2016-02-16 | The Board Of Trustees Of The University Of Illinois | Silicon nanoparticle photovoltaic devices |
US20090308441A1 (en) * | 2005-11-10 | 2009-12-17 | Nayfeh Munir H | Silicon Nanoparticle Photovoltaic Devices |
US20090090893A1 (en) * | 2007-10-04 | 2009-04-09 | Nayfeh Munir H | Nanosilicon-based room temperature paints and adhesive coatings |
US9475985B2 (en) | 2007-10-04 | 2016-10-25 | Nanosi Advanced Technologies, Inc. | Nanosilicon-based room temperature paints and adhesive coatings |
WO2011140045A1 (en) * | 2010-05-03 | 2011-11-10 | Empire Technology Development Llc | A method and apparatus for forming particles and for recovering electrochemically reactive material |
CN102844466A (en) * | 2010-05-03 | 2012-12-26 | 英派尔科技开发有限公司 | A method and apparatus for forming particles and for recovering electrochemically reactive material |
US20110316145A1 (en) * | 2010-06-29 | 2011-12-29 | National Central University | Nano/micro-structure and fabrication method thereof |
WO2012010501A1 (en) * | 2010-07-19 | 2012-01-26 | Universiteit Leiden | Process to prepare metal nanoparticles or metal oxide nanoparticles |
US9695521B2 (en) | 2010-07-19 | 2017-07-04 | Universiteit Leiden | Process to prepare metal nanoparticles or metal oxide nanoparticles |
US11827993B1 (en) | 2020-09-18 | 2023-11-28 | GRU Energy Lab Inc. | Methods of forming active materials for electrochemical cells using low-temperature electrochemical deposition |
Also Published As
Publication number | Publication date |
---|---|
WO2005123985A3 (en) | 2007-11-29 |
WO2005123985A2 (en) | 2005-12-29 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
WO2005123985A2 (en) | Germanium and germanium alloy nanoparticle and method for producing the same | |
Barrigón et al. | Synthesis and applications of III–V nanowires | |
US6762134B2 (en) | Metal-assisted chemical etch to produce porous group III-V materials | |
CA2388815C (en) | Silicon nanoparticle and method for producing the same | |
Priolo et al. | Silicon nanostructures for photonics and photovoltaics | |
US8673680B2 (en) | Nanoneedle plasmonic photodetectors and solar cells | |
Weller | Quantized semiconductor particles: a novel state of matter for materials science | |
US6838816B2 (en) | Light emitting diode with nanoparticles | |
US20110156000A1 (en) | Method of manufacturing a semiconductor device and semiconductor device | |
CN107248697B (en) | A kind of preparation method of long wavelength's InP-base DFB semiconductor laser tube core | |
JP6254608B2 (en) | Recessed contacts to semiconductor nanowires | |
EP1756335A2 (en) | Germanium and germanium alloy nanoparticle and method for producing the same | |
WO1997041591A1 (en) | Photoelectrochemical wet etching of group iii nitrides | |
CA2387142C (en) | Silicon nanoparticle stimulated emission devices | |
EP2279231B1 (en) | Method for the preparation of optically clear solution of silicon nanocrystals with short-wavelength luminescence | |
Alanis et al. | Supporting information for: Threshold reduction and yield improvement of semiconductor nanowire lasers via processing-related end-facet optimization | |
Tsuo et al. | Device applications of porous and nanostructured silicon | |
Kohl et al. | Photoelectrochemical methods for semiconductor device processing | |
Namiki | Metal-assisted chemical etching of III-V semiconductors for advanced optoelectronic device fabrication | |
Jacob et al. | Highly-efficient GaAs/AlGaAs Nanopillars and NanoLEDs via SiNx Surface Passivation | |
Meulenkamp et al. | Anodic electroluminescence of p-InP | |
Tan et al. | III-V nanowires for optoelectronic applications | |
魯旭 | The Functionalization of Surface Modified Silicon | |
Liang et al. | Light-emitting diodes on Si | |
Guichard | Growth and optical properties of CMOS-compatible silicon nanowires for photonic devices |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: UNIVERSITY OF JORDAN, THE, JORDAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ABUHASSAN, LAILA;REEL/FRAME:015804/0556 Effective date: 20040706 Owner name: BOARD OF TRUSTEES OF THE UNIVERSITY OF ILLINOIS, T Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:NAYFEH, MUNIR H.;NAYFEH, AMMAR M.;CHANG, YIA-CHUNG;REEL/FRAME:015804/0272;SIGNING DATES FROM 20040708 TO 20040726 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |
|
AS | Assignment |
Owner name: NATIONAL SCIENCE FOUNDATION,VIRGINIA Free format text: CONFIRMATORY LICENSE;ASSIGNOR:UNIVERSITY OF ILLINOIS URBANA-CHAMPAIGN;REEL/FRAME:024441/0847 Effective date: 20040722 |