Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claim(s) 1, 5, 6, 10, 13, 14, 17, 18 is/are rejected under 35 U.S.C. 103 as being unpatentable over Cheng (see PTO-892 filed 7/7/2025 Cheng et al. “Frequency conversion ...”) in view of Jarrahi et al. (US 20200111925 A1) hereafter referred to as Jarrahi. Shimatani et al. (US 20190386167 A1) hereafter referred to as Shimatani is provided as evidence of absorption in Graphene.
In regard to claim 1 Cheng teaches a graphene photodetector [see title “graphene photodetectors”, see Fig. 3] comprising:
a first electrode [see Fig. 3, either of “A GPD with two asymmetrical contact pads is designed”];
a second electrode [see Fig. 3, the other of “A GPD with two asymmetrical contact pads is designed”]; and
a graphene film [“Graphene flakes are mechanically exfoliated onto the surface of the silica layer” “Deposition of Au/Ti electrodes on the surface of the single layer graphene”] electrically connected to the first electrode and to the second electrode,
wherein the first electrode and the second electrode are formed of [“Deposition of Au/Ti electrodes on the surface of the single layer graphene”] the same conductive material,
wherein a first length of a first boundary between the first electrode and the graphene film in plan view is different [see Fig. 3 shows optical image and SEM image, compare to schematic “Herein, a MGM GPD with two asymmetrical contact pads is developed for the achievement of an effective junction in the channel” “The shift in the Fermi energy of graphene at the graphene–metal interface leads to the net photocurrent in a GPD” “when the two symmetrical graphene–metal interfaces are both exposed to the irradiation, the sum of the two photocurrents generated around the two interfaces is always close to zero due to the same magnitude and opposite polarity of the photocurrents” ] from a second length of a second boundary between the second electrode and the graphene film in plan view,
wherein the graphene film is formed so that incident light is detected by a photovoltage or a photocurrent generated [“With an effective junction in the GPD channel, both the photovoltaic and photo-thermoelectric effects contribute to the photoresponse of our fabricated GPDs” “With the increase of the bias voltage, the photoresponse bandwidth will increase as the photo-induced carriers can be separated and collected by the contacts quickly” “Photovoltaic photocurrent generation is based on the separation of photogenerated electron–hole pairs by built-in electric fields at the junctions between differently doped sections” “the photogenerated hot electrons, which play a key role in the optoelectronic response of graphene, can produce a photocurrent by the photo-thermoelectric effect” ] by conduction of both electrons and holes generated in the graphene film near at least one of the first boundary and the second boundary, and
the graphene film is formed to be irradiated with the incident light at both [this limitation is intended use, the Examiner notes that a recitation of the intended use of the claimed invention must result in a structural difference between the claimed invention and the prior art in order to patentably distinguish the claimed invention from the prior art. If the prior art structure is capable of performing the intended use, then it meets the claim, see Fig. 3 shows optical image and SEM image, compare to schematic “Herein, a MGM GPD with two asymmetrical contact pads is developed for the achievement of an effective junction in the channel” “The shift in the Fermi energy of graphene at the graphene–metal interface leads to the net photocurrent in a GPD” “when the two symmetrical graphene–metal interfaces are both exposed to the irradiation, the sum of the two photocurrents generated around the two interfaces is always close to zero due to the same magnitude and opposite polarity of the photocurrents” see page 4084 column 1, 2 ] the first boundary and the second boundary, and
but does not specifically teach:
wherein the first electrode does not overlap with the second electrode when viewed in a first direction, and the first direction is perpendicular to a second direction in which the first electrode and the second electrode face each other, the first direction is parallel to faces of the first electrode and the second electrode, said faces facing upward in thickness directions of the first electrode and the second electrode.
See Cheng teaches “two asymmetrical contact pads” and “net photocurrent” see the frequency of operation 2GHz, 3 GHz, 4GHz.
See Shimatani as evidence of absorption in Graphene, see paragraph 0192 “Generally, in a graphene transistor, photoelectric conversion of graphene has the largest contribution to an interface region between an electrode and the graphene, and the interface between the graphene and the electrode is irradiated with an electromagnetic wave, whereby electron-hole pairs are efficiently formed”.
See Jarrahi also teaches two asymmetrical contact pads, see Fig. 1A, see Fig. 5A, see paragraph 0069, 0099 and see that the “asymmetrical” is much larger than Cheng, see Jarrahi also teaches, see Abstract “In some embodiments, metallic nanostructures are integrated with graphene material to form a metallo-graphene nanocomposite” “In a number of embodiments, the photodetector operates at speeds exceeding 50 GHz” “In many applications, the minimum feature size ranges from anywhere between 10 nm and 1 μm. In several embodiments, the metal-to-metal spacing of the pattern of the nanostructures is at the sub-micrometer level. The specific distance of the spacing largely depends on the requirements of a given application. In several embodiments, the metal-to-metal spacing is less than 500 nm. In a variety of embodiments, the metal-to-metal spacing is less than 100 nm. In further embodiments, the metal-to metal spacing is less than 50 nm” “In many embodiments, the specific pattern of nanostructures within the metallo-graphene nanocomposite can be designed with dimensions that are typically dictated by the wavelengths of electromagnetic energy relevant to a particular application. In further embodiments, dimensions of the nanostructures are chosen to help achieve high responsivity. Nanostructures can be implemented in metallo-graphene nanocomposites on a subwavelength scale. In some embodiments, the geometries and dimensions of the nanostructures are designed to confine most of the photocarrier generation and conduction to the graphene and nanostructures, respectively” “In many embodiments, a 3 dB bandwidth of 425 GHz for detected optical power through a fabricated graphene photodetector was shown. In some embodiments, operation speeds exceeding 500 GHz for fabricated graphene photodetectors have been shown”, see “In a number of embodiments, metallo-graphene nanocomposites are fabricated with nanostructures laid out in a periodic pattern. In other embodiments, the nanostructures are in a non-periodic pattern. Both symmetric and asymmetric patterning of nanostructures can be implemented. Distances between components of the nanostructures within the pattern can vary and can also affect the performance of the device. Furthermore, the nanostructures themselves can be formed with different geometries, such as (but not limited to) globular, rectangular, square, split ring, H-shape, C-shape, and a variety of other geometries”, see Fig. 3A both electrodes have fingers.
See Jarrahi Fig. 1A see that the electrodes face each other in the horizontal left-right direction but do not overlap each other in the other horizontal direction perpendicular to the horizontal left-right direction, similarly in Fig. 5A.
Thus, it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains to modify Cheng to include wherein the first electrode does not overlap with the second electrode when viewed in a first direction, and the first direction is perpendicular to a second direction in which the first electrode and the second electrode face each other, the first direction is parallel to faces of the first electrode and the second electrode, said faces facing upward in thickness directions of the first electrode and the second electrode.
Thus it would be obvious to combine the references to arrive at the claimed invention.
The motivation is to increase asymetrical pad shape to increase net photocurrent to obtain increase in response to the input radiation.
In regard to claim 5 Cheng and Jarrahi as combined teaches wherein a planar shape of a first interface region in which the first electrode contacts the graphene film and [see Cheng Fig. 3, see combination Jarrahi] a planar shape of a second interface region in which the second electrode contacts the graphene film are different [see Cheng Fig. 3, see combination Jarrahi] from each other.
In regard to claim 6 Cheng and Jarrahi as combined teaches wherein an area of a first interface region in which the first electrode contacts the graphene film and [see Cheng Fig. 3 shows optical image and SEM image, compare to schematic, see combination Jarrahi] an area of a second interface region in which the second electrode contacts the graphene film are different from each other.
In regard to claim 10 Cheng and Jarrahi as combined teaches wherein at least one of the first electrode or the second electrode includes a protrusion [see combination Jarrahi, see Fig. 1A] that protrudes in the second direction.
In regard to claim 13 Cheng and Jarrahi as combined teaches wherein the graphene film is formed so that the incident light is detected by [see combination Jarrahi , see Cheng “With an effective junction in the GPD channel, both the photovoltaic and photo-thermoelectric effects contribute to the photoresponse of our fabricated GPDs” “With the increase of the bias voltage, the photoresponse bandwidth will increase as the photo-induced carriers can be separated and collected by the contacts quickly” “Photovoltaic photocurrent generation is based on the separation of photogenerated electron–hole pairs by built-in electric fields at the junctions between differently doped sections” “the photogenerated hot electrons, which play a key role in the optoelectronic response of graphene, can produce a photocurrent by the photo-thermoelectric effect” see Fig. 3 “Herein, a MGM GPD with two asymmetrical contact pads is developed for the achievement of an effective junction in the channel” “The shift in the Fermi energy of graphene at the graphene–metal interface leads to the net photocurrent in a GPD” “when the two symmetrical graphene–metal interfaces are both exposed to the irradiation, the sum of the two photocurrents generated around the two interfaces is always close to zero due to the same magnitude and opposite polarity of the photocurrents” ] the photovoltage or the photocurrent generated by the conduction of both the electrons and the holes generated in the graphene film near both of the first boundary and the second boundary.
In regard to claim 14 Cheng and Jarrahi as combined teaches wherein the first electrode includes a first protrusion [see combination Jarrahi, see Jarrahi Fig. 1A] that protrudes in the second direction, but does not specifically teach wherein the second electrode includes a second protrusion that protrudes in the second direction, and wherein a width in the first direction of the first protrusion is different from a width in the first direction of the second protrusion.
See that asymmetric electrodes are taught by Cheng, see Jarrahi Fig. 3A has fingers on both electrodes, see Jarrahi paragraph 0068 “In a number of embodiments, metallo-graphene nanocomposites are fabricated with nanostructures laid out in a periodic pattern. In other embodiments, the nanostructures are in a non-periodic pattern. Both symmetric and asymmetric patterning of nanostructures can be implemented. Distances between components of the nanostructures within the pattern can vary and can also affect the performance of the device. Furthermore, the nanostructures themselves can be formed with different geometries, such as (but not limited to) globular, rectangular, square, split ring, H-shape, C-shape, and a variety of other geometries”, see also geometry “In some embodiments, the geometries and dimensions of the nanostructures are designed to confine most of the photocarrier generation and conduction to the graphene and nanostructures, respectively”.
Thus, it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains to modify Cheng to include wherein the second electrode includes a second protrusion that protrudes in the second direction, and wherein a width in the first direction of the first protrusion is different from a width in the first direction of the second protrusion.
Thus it would be obvious to combine the references to arrive at the claimed invention.
The motivation is to optimize asymetrical pad shape and geometry for an application using plurality of fingers to adjust resistance of the device.
In regard to claim 17 Cheng and Jarrahi as combined teaches wherein the first electrode includes no protrusion [see combination Jarrahi, see Jarrahi Fig. 1A, there are a plurality of electrode fingers on the left but no fingers on the right] that protrudes in the second direction, and wherein the second electrode includes a plurality of second protrusions that protrude in the second direction.
In regard to claim 18 Cheng and Jarrahi as combined teaches wherein the second electrode includes at least three second protrusions that protrude in the second direction [see combination Jarrahi, see Jarrahi Fig. 1A, there are a plurality of electrode fingers on the left but no fingers on the right] , but does not specifically teach wherein the first electrode includes a single first protrusion that protrudes in the second direction.
However see that in Jarrahi Fig. 1A the electrode on the right can be described as a base portion connected to the bias and a single protrusion pointing toward the electrode on the left., see Jarrahi Fig. 3A has fingers on both electrodes, see Jarrahi paragraph 0068 “In a number of embodiments, metallo-graphene nanocomposites are fabricated with nanostructures laid out in a periodic pattern. In other embodiments, the nanostructures are in a non-periodic pattern. Both symmetric and asymmetric patterning of nanostructures can be implemented. Distances between components of the nanostructures within the pattern can vary and can also affect the performance of the device. Furthermore, the nanostructures themselves can be formed with different geometries, such as (but not limited to) globular, rectangular, square, split ring, H-shape, C-shape, and a variety of other geometries”, see also geometry “In some embodiments, the geometries and dimensions of the nanostructures are designed to confine most of the photocarrier generation and conduction to the graphene and nanostructures, respectively”.
Thus, it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains to modify Cheng to include wherein the first electrode includes a single first protrusion that protrudes in the second direction.
Thus it would be obvious to combine the references to arrive at the claimed invention.
The motivation is to optimize asymetrical pad shape and geometry for an application by adjusting the number of fingers to adjust resistance of the device.
Claim(s) 11, 3, 12, 7, 8 is/are rejected under 35 U.S.C. 103 as being unpatentable over Cheng and Jarrahi as combined and further in view of Shimatani et al. (US 20190386167 A1) hereafter referred to as Shimatani. Lin et al. (US 20200004080 A1) hereafter referred to as Lin is provided as evidence.
In regard to claim 11 Cheng and Jarrahi as combined does not teach wherein either the first boundary or the second boundary is covered with a light shielding mask.
See Cheng teaches “a MGM GPD with two asymmetrical contact pads is developed for the achievement of an effective junction”.
See Jarrahi Fig. 5A, see optical beam energy is on the left.
See Shimatani teaches asymmetry see Fig. 15 see paragraph 0121, 0191, 0209 “as shown in FIGS. 15A and 15B, a light shielding portion 27 is provided in an optical path of an electromagnetic wave incident on either one of interfaces between graphenes 1, 2 and an electrode 3 or 4” “Generally, in a graphene transistor, photoelectric conversion of graphene has the largest contribution to an interface region between an electrode and the graphene, and the interface between the graphene and the electrode is irradiated with an electromagnetic wave, whereby electron-hole pairs are efficiently formed. See that Shimatani teaches that the interface is where the photogeneration occurs.
Thus, it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains to modify Cheng to include wherein either the first boundary or the second boundary is covered with a light shielding mask.
Thus it would be obvious to combine the references to arrive at the claimed invention.
The motivation is increase asymmetry by shielding the smaller electrode interface from receiving light.
In regard to claim 3 Cheng, Jarrahi and Shimatani as combined does not teach wherein the light shielding mask is formed of an insulative material opaque to light having a certain wavelength.
See evidence of Lin paragraph 0025 “the material of the light-shielding layer SM may include any light-shielding material commonly known to people having ordinary skills in the art, e.g., molybdenum, molybdenum-aluminum-molybdenum, titanium-aluminum-titanium, or other metals which do not allow light to pass through or black resin, so as to shield light rays”.
It would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains to use " wherein the light shielding mask is formed of an insulative material opaque to light having a certain wavelength ", since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. In re Leshin, 125 USPQ 416.
In regard to claim 12 Cheng, Jarrahi and Shimatani as combined does not teach wherein the light shielding mask is formed of a light reflective metal or a semiconductor opaque to light having a certain wavelength, and the light shielding mask is placed on an insulation layer, and the portion of the insulation where the mask is located is then positioned over either of the first electrode or the second electrode.
See Cheng understands the use of insulation for isolating heavily doped semiconductor, see Fig. 3 see “A heavily doped silicon chip with a 300 nm-thick thermal oxidization SiO2 layer was utilized as the substrate (Fig. 3b)”, see the direction of incident light shown is from above, not below i.e. the light is not shown as passing through the substrate.
See evidence of Lin paragraph 0025 “the material of the light-shielding layer SM may include any light-shielding material commonly known to people having ordinary skills in the art, e.g., molybdenum, molybdenum-aluminum-molybdenum, titanium-aluminum-titanium, or other metals which do not allow light to pass through or black resin, so as to shield light rays”.
It would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains to use "wherein the light shielding mask is formed of a light reflective metal or a semiconductor opaque to light having a certain wavelength, and the light shielding mask is placed on an insulation layer, and the portion of the insulation where the mask is located is then positioned over either of the first electrode or the second electrode", since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. In re Leshin, 125 USPQ 416.
In regard to claim 7 Cheng and Jarrahi as combined does not teach wherein a light shielding mask is disposed on an electrode, from among the first electrode and the second electrode, having an interface region, from among the first interface region and the second interface region, with a smaller area.
See Cheng teaches “a MGM GPD with two asymmetrical contact pads is developed for the achievement of an effective junction”.
See Shimatani teaches asymmetry see Fig. 15 see paragraph 0121, 0191, 0209 “as shown in FIGS. 15A and 15B, a light shielding portion 27 is provided in an optical path of an electromagnetic wave incident on either one of interfaces between graphenes 1, 2 and an electrode 3 or 4” “Generally, in a graphene transistor, photoelectric conversion of graphene has the largest contribution to an interface region between an electrode and the graphene, and the interface between the graphene and the electrode is irradiated with an electromagnetic wave, whereby electron-hole pairs are efficiently formed. See that Shimatani teaches that the interface is where the photogeneration occurs.
Thus, it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains to modify Cheng to include wherein a light shielding mask is disposed on an electrode, from among the first electrode and the second electrode, having an interface region, from among the first interface region and the second interface region, with a smaller area.
Thus it would be obvious to combine the references to arrive at the claimed invention.
The motivation is increase asymmetry by shielding the smaller electrode interface from receiving light.
In regard to claim 8 Cheng and Jarrahi as combined does not specifically teach a photodetector array comprising: a plurality of graphene photodetectors according to claim 1 disposed in a coplanar arrangement.
See Shimatani paragraph 0005, 0162 “a purpose of the present invention is to provide an electromagnetic wave detector, an electromagnetic wave detector array” “FIG. 12A shows an electromagnetic wave detector array according to a ninth embodiment of the present invention, which is generally represented as 10000. The electromagnetic wave detector array 10000 has pixels 1000 arranged in 2×2, but the number of pixels to be arranged is not limited to this”.
Thus, it would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains to modify Cheng to include photodetector array comprising: a plurality of graphene photodetectors according to claim 1 disposed in a coplanar arrangement.
Thus it would be obvious to combine the references to arrive at the claimed invention.
The motivation is ease of manufacture by coplanar arrangement and that array gives more information such as spatial variation.
Response to Arguments
Applicant's arguments filed 12/26/2025 have been fully considered but they are not persuasive.
On page 1-3 the Applicant argues “The structure of Cheng's device, particularly its concentric or U-shaped electrode configuration as suggested by the schematic in Cheng's Figures 3 and 5, results in one electrode (the inner one) being surrounded or enclosed by the other (the outer one) in the device's plane. When viewed from any direction parallel to the electrode, parts of the electrodes must inherently overlap or enclose each other in projection. Anticipation requires the presence in a single prior art reference disclosure of each and every element of the claimed invention, arranged as in the claim. In view of the distinction of claim 1 noted above, at least one claimed element is not present in Cheng. Hence, Cheng does not anticipate claim 1” .
The Examiner responds that the new limitations of the amendment are shown by the secondary reference in the amended rejection above.
On page 1-3 the Applicant argues “It is noted that Shimatani teaches a method to solve the same problem by introducing a light shielding portion (27) to deliberately block light to one interface, achieving illumination asymmetry. Thus, Shimatani does not teach or suggest the claimed features of "the graphene film is formed to be irradiated with the incident light at both the first boundary and the second boundary”.
The Examiner responds that primary reference teaches this limitation and also, that this is intended use, and the structure shows this limitation as explained in the rejection above, see net photocurrent.
On page 3, 4, 5 the Applicant argues about Gao reference and light at both boundaries.
The Examiner responds that as stated above primary reference teaches this limitation and also, that this is intended use, and the structure shows this limitation as explained in the rejection above, see net photocurrent.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to SITARAMARAO S YECHURI whose telephone number is (571)272-8764. The examiner can normally be reached M-F 8:00-4:30 PM.
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/SITARAMARAO S YECHURI/ Primary Examiner, Art Unit 2893