DETAILED ACTION
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 .
Election/Restrictions
Applicant’s election without traverse of group I, claims 1-11, in the reply filed on 01/27/2026 is acknowledged.
Claims 12-19 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on 01/27/2026.
Claim Rejections - 35 USC § 102
The following is a quotation of the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action:
A person shall be entitled to a patent unless –
(a)(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.
Claims 1, 4 and 9-10 are rejected under 35 U.S.C. 102(a)(2) as being anticipated by Walukiewicz et al. (US 2013/0074912 A1) (cited in IDS dated 01/15/2025).
Regarding claim 1, Walukiewicz discloses a method of making a photovoltaic device (photovoltaic device shown in figure 1), comprising:
providing an absorber layer (absorber layer made of CdTeySe1-y material wherein 0.74<y<0.85) on a layer stack (stack of a MgF2 layer, a glass layer, a SnO2:F layer and a CdS layer) (see fig. 1 and fig. 4) ([0020] and [0024-0027]);
wherein: the absorber layer is an alloy comprising cadmium, tellurium, and selenium (CdTeySe1-y material) (fig. 4, [0020] and [0024-0027]);
the absorber layer includes a varying concentration of selenium (the composition of Se is graded) (see fig. 4) ([0024] and [0026]) such that there is a higher concentration of selenium near a front interface (CdS interface side) relative to a back interface (side opposite CdS interface side) (as disclosed in [0026], the conductive band of CdTeySe1-y material is matched to CdS window at the interface, and as shown in figure 4 such matching occurs when Te is around 0.74, in other words when Se is 0.26, and the composition of Se is graded from 0.26 at the CdS interface side to 0.15 at the side opposite the CdS interface side) (see fig. 4 and paragraphs [0024] and [0026]); and
an atomic concentration of selenium varies non-linearly across a thickness of the absorber layer (the composition of Se is graded) (see fig. 4) ([0024] and [0026]).
Regarding claim 4, Walukiewicz further discloses that the alloy comprises a compound having a formula CdTe1-xSex (see fig. 4) ([0024] and [0026]), wherein a Se substitution fraction, x, has a value less than 0.3 throughout the absorber layer (Se concentration varies from 0.15-0.26 as discussed above) ((see fig. 4) ([0024] and [0026]).
Regarding claim 9, Walukiewicz further discloses that the layer stack comprises: a transparent conductive layer (SnO2:F layer, fig. 1) disposed on a support (glass, fig. 1); and a buffer layer (CdS layer) disposed between the transparent conductive layer (SnO2:F layer) and the absorber layer (CdTe1-xSex layer) (see fig. 4 for configuration).
Regarding claim 10, Walukiewicz further discloses that the absorber layer comprises
a first region (CdS interface side) and a second region (side opposite to CdS interface side or ohmic contact side) (see fig. 1), the first region (CdS interface side) disposed proximate to the layer stack (stack of a MgF2 layer, a glass layer, a SnO2:F layer and a CdS layer) relative to the second region (side opposite to CdS interface side) (see fig. 1);
the first region has a thickness between 100 nanometers to 3000 nanometers (the absorbing layer has a thickness of 4 micron or 4000 nm, [0027], and thus bottom half with a thickness of 2000 nm is interpreted as the first region);
the second region has a thickness between 100 nanometers to 3000 nanometers (the absorbing layer has a thickness of 4 micron or 4000 nm, [0027], and thus top half with a thickness of 2000 nm is interpreted as the second region);
an average atomic concentration of selenium in the first region is greater than an average atomic concentration of selenium in the second region (as disclosed in [0026], the conductive band of CdTeySe1-y material is matched to CdS window at the interface, and as shown in figure 4 such matching occurs when Te is around 0.74, in other words when Se is 0.26, and the composition of Se is 0.26 at the CdS interface side, and the composition of Se is 0.15 at the ohmic or metal contact) (see fig. 4 and paragraphs [0024] and [0026]).
Walukiewicz further discloses that the absorber layer is compositionally graded from the composition that matches the conduction band edges at the interface of the CdS window and the CdTexM1-x absorber to CdTe close to the surface ([0026]). Thus, Walukiewicz explicitly discloses that the concentration of Se approaches zero (for CdTe material) at the ohmic contact side, which implies that the ratio would be greater than 2 (0.26/x, when x approaches zero, such as 0.005, the ratio is 52).
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claims 2 and 3 are rejected under 35 U.S.C. 103 as being unpatentable over Walukiewicz as applied above, and further in view of Alivisatos et al. (US 2009/0217973 A1).
Regarding claim 2, Walukiewicz does not explicitly disclose the step of providing an absorber layer comprises: forming a first film, comprising cadmium and selenium, over the layer stack; forming a second film, comprising cadmium and tellurium, over the first film; applying a CdCl2 treatment; and heating the layer stack.
Alivisatos discloses a method of making a solar cell (400, figures 4A, 4B) wherein the absorber layer comprises forming a first film (450), comprising cadmium and selenium ([0018-0019]) and forming a second film (440), comprising cadmium and tellurium ([0018-0019]); applying a CdCl2 treatment ([0018-0019]) and heating the stack (sintering step) ([0018-0019]).
Therefore, it would have been obvious to one of ordinary skill in the art at the time of the invention to have process steps as taught by Alivisatos to form the absorber layer of Walukiewicz because applying a known technique to a known device (method, or product) ready for improvement to yield predictable results (to form the absorber layer) is obvious (KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 415-421, 82 USPQ2d 1385, 1395-97 (2007)).
Regarding claim 3, Walukiewicz as modified does not disclose that the second film is thicker than the first film. However, in absence of evidence of criticality, selection of element’s dimension is considered to be a matter of design choice, depending upon the dimensions and gradient present in the installation site, among other considerations. In the absence of evidence of criticality, selection of first and second film’s thicknesses as claimed is considered obvious to one having ordinary skill in the art. Also note that in Gardner v. TEC Systems, Inc., 725 F.2d 1338, 220 USPQ 777 (Fed. Cir. 1984), cert. denied, 469 U.S. 830, 225 USPQ 232 (1984), the Federal Circuit held that, where the only difference between the prior art and the claims was a recitation of relative dimensions of the claimed device and a device having the claimed relative dimensions would not perform differently than the prior art device, the claimed device was not patentably distinct from the prior art device.
Claims 5 and 11 are rejected under 35 U.S.C. 103 as being unpatentable over Walukiewicz as applied above.
Regarding claim 5, Walukiewicz further discloses that the alloy comprises a compound having a formula CdTe1-xSex (see fig. 4) ([0024] and [0026]), wherein a Se substitution fraction, x, has a value of 0.26 at the front interface (as disclosed in [0026], the conductive band of CdTeySe1-y material is matched to CdS window at the interface, and as shown in figure 4 such matching occurs when Te is around 0.74, in other words when Se is 0.26) (see fig. 4 and paragraphs [0024] and [0026]). Although the disclose Se substitution fraction (0.26) is not within the claimed range of 0.2-0.25, it is close to the claimed range.
MPEP clearly states that “a prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are merely close” (Titanium Metals Corp. of America v. Banner, 778 F.2d 775, 783, 227 USPQ 773, 779 (Fed. Cir. 1985)). MPEP §2144.05.
Claimed value such as 0.25 is close to disclosed value 0.26, and one skilled in the solar art would have acknowledged that there would not such a big shift in absorption, and the absorber layer would have expected to function same way. Thus, a prima facie case of obviousness exists.
Regarding claim 11, although Walukiewicz does not explicitly disclose that absorber layer further comprises S or O, Walukiewicz further discloses that absorber layer is made of CdTeSe, CdTeS or CdTeO (see [0011] and [0024]). Therefore, it would have been obvious to one of ordinary skill in the art at the time the invention was made to have combined CdTeSe with CdTeS or CdTeO to have form have formed an absorber layer because “it is prima facie obvious to combine two compositions each of which is taught by the prior art to be useful for the same purpose, in order to form a third composition to be used for the very same purpose.... [T]he idea of combining them flows logically from their having been individually taught in the prior art.” In re Kerkhoven, 626 F.2d 846, 850, 205 USPQ 1069, 1072 (CCPA 1980). Accordingly, Walukiewicz as modified discloses that the absorber layer further comprises sulfur or oxygen.
Claims 6-8 are rejected under 35 U.S.C. 103 as being unpatentable over Walukiewicz as applied above, and further in view of Basol (US 2011/0284065 A1).
Regarding claims 6 and 7, Walukiewicz does not explicitly disclose that disposing a p+ type semiconducting layer over the absorber layer, wherein the p+ type semiconducting layer comprises a material selected from: zinc telluride, magnesium telluride, manganese telluride, beryllium telluride, mercury telluride, arsenic telluride, antimony telluride, copper telluride, elemental tellurium, or combinations thereof, wherein the p+ type semiconducting layer comprises a dopant, wherein the dopant comprises: copper, gold, nitrogen, phosphorus, antimony, arsenic, silver, bismuth, sulfur, sodium, or combinations thereof.
Basol discloses a method of making a photovoltaic device (device structure 39) (process steps are shown in figures 3A-3D), wherein mixed interlayer (38) is formed between an absorber layer (33) and contact layer (37) ([0023]) to improve the ohmic contacts to CdTe absorber ([0007]).
Therefore, it would have been obvious to one of ordinary skill in the art at the time of the invention to have used the mixed interlayer as taught by Basol between the absorber and the metal contacts of Walukiewicz to improve the ohmic contacts.
Walukiewicz as modified by Basol further discloses that layer is made of zinc telluride further comprises copper ([0020-0023]), which is interpreted as the p+ dopant. Thus, it would form the p+ type semiconductor layer as in the case of the instant application.
Regarding claim 8, Walukiewicz further discloses that disposing a back contact layer (ohmic contact, fig. 1) over the absorber layer (CdTe1-xSex layer) (fig. 1). However, Walukiewicz does not disclose that the back contact layer comprises at least one of: gold, platinum, molybdenum, tungsten, tantalum, titanium, palladium, aluminum, chromium, nickel, silver, or graphite.
Basol discloses a method of making a photovoltaic device (device structure 39) (process steps are shown in figures 3A-3D), wherein contact layer (37) is made of Ni, Mo, Ta, Ti, Cr or Al ([0023]).
Therefore, it would have been obvious to one of ordinary skill in the art at the time of the invention to have used Ni, Mo, Ta, Ti, Cr or Al as taught by Basol to form the back contact layer of Walukiewicz because selection of a known material based on its suitability for its intended use supported a prima facie obviousness determination in Sinclair & Carroll Co. v. Interchemical Corp., 325 U.S. 327, 65 USPQ 297 (1945). See MPEP § 2144.07.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to GOLAM MOWLA whose telephone number is (571)270-5268. The examiner can normally be reached M-Th, 7am - 4pm.
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/GOLAM MOWLA/ Primary Examiner, Art Unit 1721
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