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[Zhao Ma](https://orcid.org/0000-0003-0151-8592), [Takaaki Mano](https://orcid.org/0000-0002-6955-260X), [Akihiro Ohtake](https://orcid.org/0000-0002-3519-4613), [Takashi Kuroda](https://orcid.org/0000-0001-6445-7673)

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[Effects of arsenic oxides on GaAs surfaces on photoluminescence properties of buried InGaAs quantum wells: Dependence on initial surfaces before oxidation](https://mdr.nims.go.jp/datasets/82d1dfa7-36da-42e3-8e4d-0767e63600ea)

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Effects of arsenic oxides on GaAs surfaces on photoluminescence properties of buried InGaAs quantum wells: Dependence on initial surfaces before oxidationViewOnlineExportCitationRESEARCH ARTICLE |  JUNE 23 2025Effects of arsenic oxides on GaAs surfaces onphotoluminescence properties of buried InGaAs quantumwells: Dependence on initial surfaces before oxidationZhao Ma   ; Takaaki Mano   ; Akihiro Ohtake  ; Takashi Kuroda J. Appl. Phys. 137, 243102 (2025)https://doi.org/10.1063/5.0274742Articles You May Be Interested InMolecular beam epitaxy growth of GaAsBi/GaAs/AlGaAs separate confinement heterostructuresAppl. Phys. Lett. (October 2012)Chemical beam epitaxy growth of self-assembled InAs/InP quantum dotsJ. Vac. Sci. Technol. B (July 2001)Preparation of a clean Ge(001) surface using oxygen plasma cleaningJ. Vac. Sci. Technol. B (April 2013) 27 June 2025 02:47:20https://pubs.aip.org/aip/jap/article/137/24/243102/3350691/Effects-of-arsenic-oxides-on-GaAs-surfaces-onhttps://pubs.aip.org/aip/jap/article/137/24/243102/3350691/Effects-of-arsenic-oxides-on-GaAs-surfaces-on?pdfCoverIconEvent=citejavascript:;https://orcid.org/0000-0003-0151-8592javascript:;https://orcid.org/0000-0002-6955-260Xjavascript:;https://orcid.org/0000-0002-3519-4613javascript:;https://orcid.org/0000-0001-6445-7673https://crossmark.crossref.org/dialog/?doi=10.1063/5.0274742&domain=pdf&date_stamp=2025-06-23https://doi.org/10.1063/5.0274742https://pubs.aip.org/aip/apl/article/101/18/181103/23331/Molecular-beam-epitaxy-growth-of-GaAsBi-GaAshttps://pubs.aip.org/avs/jvb/article/19/4/1467/591119/Chemical-beam-epitaxy-growth-of-self-assembledhttps://pubs.aip.org/avs/jvb/article/31/3/031201/102398/Preparation-of-a-clean-Ge-001-surface-using-oxygenhttps://e-11492.adzerk.net/r?e=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&s=UimVfH0rWYLuPfK9ItUWENP_4DUEffects of arsenic oxides on GaAs surfaces onphotoluminescence properties of buried InGaAsquantum wells: Dependence on initial surfacesbefore oxidationCite as: J. Appl. Phys. 137, 243102 (2025); doi: 10.1063/5.0274742View Online Export Citation CrossMarkSubmitted: 8 April 2025 · Accepted: 29 May 2025 ·Published Online: 23 June 2025Zhao Ma,1,2,a) Takaaki Mano,1,a) Akihiro Ohtake,1 and Takashi Kuroda1,2AFFILIATIONS1National Institute for Materials Science, Research Center for Electronic and Optical Materials, Tsukuba, Ibaraki 305-0044, Japan2Department of Applied Chemistry, Graduate School of Engineering, Kyushu University, Fukuoka 819-0395, Japana)Authors to whom correspondence should be addressed: MA.Zhao@nims.go.jp and MANO.Takaaki@nims.go.jpABSTRACTWe have studied the oxidation states and photoluminescence (PL) properties of GaAs(100) samples that incorporated buried InGaAsquantum well (QW) structures prepared by molecular-beam epitaxy (MBE). The surfaces of the MBE-grown GaAs(100) samples were con-trolled so that they were either As-rich c(4 × 4)α, Ga-rich (4 × 6) or Se-terminated (2 × 1) structures prior to oxidation. We found that theAs/Ga composition ratio at the initial GaAs surface strongly affects the oxidation processes and the resultant PL properties. An oxidizedsample whose initial As-rich surface contains a large amount of As oxide, has a significantly lower PL intensity than As-deficient samples.The reduction of the surface As coverage simply by preparing Ga-rich (4 × 6) and Se-terminated (2 × 1) surfaces has a positive effect on thePL properties, which is maintained even after the oxidation has progressed into deeper layers after longer air exposure, e.g., six months.© 2025 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license(https://creativecommons.org/licenses/by/4.0/). https://doi.org/10.1063/5.0274742I. INTRODUCTIONWhen III–V semiconductor structures are exposed to air, theirsurfaces are gradually oxidized by the oxygen gas and/or watervapor in the air.1–3 It is well known that the surface oxides create ahigh density of surface states, which has several negative impactson their properties, such as non-radiative recombination,Fermi-level pinning effects, and charge trapping.4–9 The surfaceoxidation of III–V semiconductors has been a long-standing issueas regards improving the optical and/or electrical properties ofIII–V-based devices.Recent advanced nanotechnologies allow us to fabricate highlycomplex nanostructures, such as nanowires, nanopillars, nanoholes,and nanodots.10–18 With these nanostructures, the surface-relatedissues are more critical due to their large surface area and/or theshort distance between the core region and the oxidized surfaces.In addition, it has also been suggested that the photonic propertiesof the nanostructures are highly sensitive to the fluctuation of thetrapped charges caused by the surface states8,9,19,20 Consequently,research on III–V semiconductor surfaces that have been exposedto the air is again attracting great attention.One of the most promising ways of dealing with theseoxide-related issues is surface termination using group-VI atomssuch as sulfur (S) and selenium (Se).21–32 It is generally believedthat VI-terminated surfaces are more stable against oxidation thannon-passivated III–V surfaces.26,33,34 Recently, we have studied theeffect of the S-termination of GaAs (100) surfaces on the photolu-minescence (PL) properties of buried InGaAs quantum wells(QW).35 We found that wet-chemical treatment using ammoniumsulfide solution is effective in suppressing the formation of Asoxide and that the PL properties are improved as the amount of Asoxide is reduced. An important implication of the results is that theformation of As oxide could be suppressed by simply reducing theamount of As oxide in the GaAs sample, resulting in improved PLproperties.Journal ofApplied PhysicsARTICLE pubs.aip.org/aip/japJ. Appl. Phys. 137, 243102 (2025); doi: 10.1063/5.0274742 137, 243102-1© Author(s) 2025 27 June 2025 02:47:20https://doi.org/10.1063/5.0274742https://doi.org/10.1063/5.0274742https://pubs.aip.org/action/showCitFormats?type=show&doi=10.1063/5.0274742http://crossmark.crossref.org/dialog/?doi=10.1063/5.0274742&domain=pdf&date_stamp=2025-06-23https://orcid.org/0000-0003-0151-8592https://orcid.org/0000-0002-6955-260Xhttps://orcid.org/0000-0002-3519-4613https://orcid.org/0000-0001-6445-7673mailto:MA.Zhao@nims.go.jpmailto:MANO.Takaaki@nims.go.jphttps://creativecommons.org/licenses/by/4.0/https://creativecommons.org/licenses/by/4.0/https://doi.org/10.1063/5.0274742https://pubs.aip.org/aip/japIn this study, we report on the effect of the As/Ga surfacestoichiometry on oxide formation and the resultant PL properties.For this purpose, we prepared GaAs (100) samples with clean andwell-defined surfaces and buried InGaAs QWs using molecularbeam epitaxy (MBE) We then studied the long-term changes inthe PL properties of QWs upon oxidation. A GaAs(100) surfaceis known to exhibit various reconstructed structures dependingon the surface stoichiometry;36 As-rich c(4 × 4)α [Fig. 1(a)]37 andGa-rich (4 × 6) [Fig. 1(b)]38 surfaces were chosen for this study.In addition, we prepared a (2 × 1) surface terminated with Se,32with no As atoms in the four surface layers, as shown in Fig. 1(c).Precise control of the structure and stoichiometry of the surfacesenables us to study the effects of the surface stoichiometry on theoxide formation and the resultant PL properties. Using x-ray pho-toemission spectroscopy (XPS), we show that more (less) Gaoxide (As oxide) is formed on Ga-rich (As-rich) surfaces, andthat samples containing more As oxide exhibit degraded PL prop-erties. We reveal that controlling the surface so that it is Ga-rich(As deficient) is effective for enhancing the optical properties ofthe buried structures.II. EXPERIMENTALWe employed two standard MBE systems, each serving dif-ferent purposes. The first MBE system was used to grow our QWsamples, as well as to prepare As-rich and Ga-rich surfaces. Thesecond MBE chamber was just used for the Se treatment. As astarting material, we prepared a single InGaAs QW structuregrown on a GaAs (001) substrate using the first MBE system. A300 nm-thick GaAs buffer layer was grown at 580 °C on a ther-mally cleaned substrate. Then, a 10 nm In0.12Ga0.88As QW wasgrown at 490 °C, followed by a 100 nm GaAs capping layer grownat the same temperature. To suppress unintentional oxidationduring the latter procedure, the sample prepared in the first MBEchamber was covered with amorphous As layers before removal.The amorphous As layers were formed by supplying As2 flux(1 × 10−5 Torr beam equivalent pressure (BEP)) for 30 min atroom temperature. The sample was then divided into severalpieces. Two pieces were reloaded into the first MBE chamber forthe formation of As-rich c(4 × 4)α and Ga-rich (4 × 6) reconstruc-tions.38,39 A Ga-rich (4 × 6) surface was prepared by heating thesample at around 540 °C without As4 flux for 5 min. To form anAs-rich c(4 × 4)α surface, the sample was heated at around 540 °Cunder the As4 flux (BEP = 5 × 10−6 Torr) and cooled to 350 °Cunder the As4 flux. Another piece of the sample was placed in thesecond MBE system for the Se treatment: the sample was firstheated at around 540 °C under As4 flux to remove the amorphousAs layers and to form an As-rich (2 × 4) reconstruction. Then the(2 × 4) sample was further heated to 600 °C under the Se flux(without As4 flux) to form a Se-terminated (2 × 1) surface. Thesample was then cooled to 350 °C under the Se flux. All thesamples were simultaneously removed from the MBE systemsinto the air.Immediately after removing these samples into the air, webegan to study the temporal variation in the intensities of the PLand XPS signals for up to 14 days of air exposure. We used the PLFIG. 1. (a)–(c) Structure models for GaAs (001)-c(4 × 4)α, (4 × 6), and (2 × 1)-Se surfaces. The unit cells are indicated by rectangles. (d)–(f ) RHEED pattens of thesesurfaces obtained in the [110] and [1–10] directions. These sample surfaces were prepared by MBE.Journal ofApplied PhysicsARTICLE pubs.aip.org/aip/japJ. Appl. Phys. 137, 243102 (2025); doi: 10.1063/5.0274742 137, 243102-2© Author(s) 2025 27 June 2025 02:47:20https://pubs.aip.org/aip/japmeasurements to evaluate the number of nonradiative recombina-tion centers at the surfaces. The carriers photoexcited by the laserin the capping layers migrate to the surfaces with certain probabili-ties. When nonradiative recombination centers are formed on thesurfaces, some carriers recombine nonradiatively, resulting in thedegradation of the PL intensity of the QW.35 For the PL measure-ments, we employed a Nd:YVO4 laser at a wavelength of 532 nm.The emitted PL signals were detected by a 30 cm spectrometerattached to a cooled charge-coupled device (CCD) camera. All thePL measurements were conducted at 4 K.The surface chemical conditions were analyzed using an XPSsystem (Surface Science Instruments M-Probe). The XPS measure-ments were performed using monochromatic Al Kα radiation(1486.6 eV) at room temperature. Photoelectrons were detected atan angle of 35° from the surface. The As 3d and Ga 3d spectrawere measured and fitted using a Voigt function with the ratio ofGaussian to Lorentzian components fixed at 2.5. Peak separationsof 0.70 and 0.45 eV, respectively, were assumed for the 5/2 and 3/2spin-orbit components of As 3d and Ga 3d. To eliminate the sensi-tivity differences in photoelectron detection among various ele-ments and electron shells, the integrated measured intensities ofeach component (Ga-As, Ga-O, As-O, etc.) were divided byScofiled’s relative sensitivity factors, and were then normalized tothe total intensity of the Ga 3d signals.40III. RESULTS AND DISCUSSIONFigures 1(d)–1(f ) show typical reflection high-energy electrondiffraction (RHEED) patterns of the As-rich c(4 × 4)α, Ga-rich(4 × 6), and Se-terminated (2 × 1) surfaces prepared in our MBEsystems. The well-defined and sharp patterns indicate the forma-tion of flat, large terraces, which is characteristic of samples pre-pared by MBE. The proposed structural models for these surfacesare shown in Figs. 1(a)–1(c).32,38,39 The As-rich c(4 × 4)α recon-structed surface consists of three Ga-As dimers per unit cell on theAs-terminated surface (As coverage is 1.0 Ml), while there is a verysmall quantity of As atoms on the Ga-rich (4 × 6) surface: theAs-coverage is only 1/12Ml. In the Se-terminated sample, theamount of As at the surface layers is further reduced; Se atomscompletely replace As atoms in the 1st and 2nd layers. As wereport below, the three samples exhibit altogether different PLproperties after being exposed to air.In this work, we mainly analyze the low-temperature PLproperties at 4 K, since the PL at higher temperatures couldsuffer from complicated dynamics, such as carrier thermal escapefrom the QW and enhancement of nonradiative recombination.Figures 2(a)–2(c) show the low-temperature PL spectra for thethree samples, which were measured immediately after the sampleshad been removed into the air (within 30 min). All the samplesexhibit a distinct PL emission peak around 860 nm from theFIG. 2. Low-temperature PL spectra of (a) As-rich c(4 × 4)α, (b) Ga-rich (4 × 6), and (c) Se-terminated (2 × 1) samples. The integrated intensities of these spectra areplotted in (d).Journal ofApplied PhysicsARTICLE pubs.aip.org/aip/japJ. Appl. Phys. 137, 243102 (2025); doi: 10.1063/5.0274742 137, 243102-3© Author(s) 2025 27 June 2025 02:47:20https://pubs.aip.org/aip/japInGaAs QW. The assignment of the PL spectral peak, togetherwith other peaks, which originate from the GaAs barrier layer, wasconfirmed with the semilogarithmic plot shown in a (Fig. S1 in thesupplementary material). There is a slight but clear difference intheir intensities: the integrated PL intensities of the Ga-rich sampleand Se-terminated samples were 1.11 and 1.16 times greater,respectively, than that of the As-rich sample, as shown in Fig. 2(c).Next, we studied the temporal changes in the PL intensity ofthe three samples after exposure to air. Figure 3 shows the inte-grated PL intensities of the three samples plotted as a function ofthe exposure time. The Ga-rich and As-rich samples both showlarge decreases in their PL intensities during the first 2 h followedby gradual decreases. The degradation is attributed to the oxidationof clean GaAs surfaces, as we will show below. The PL intensitiesfor Ga-rich and As-rich samples behave similarly as a function ofthe exposure time, namely they are decreased by 13% and 11%,respectively. Here, it is important to note that the As-rich samplealways exhibits a lower PL intensity (∼11%) than the Ga-richsample throughout the oxidation processes. This means that theeffects of the initial surface reconstruction on the PL properties aresustained for at least 30 days.The PL intensity of the Se-terminated sample also decreasedafter the sample was exposed to air. However, comparing theresults for samples that had no Se treatment, we found that the PLproperty degraded slightly more slowly, which is probably due tothe suppression of oxidation by the Se termination. On the otherhand, when the samples were left in air for longer, the PL intensitycontinuously decreased, and was finally saturated at nearly thesame level as the Ga-rich sample after 5 days, but was alwayshigher than that of the As-rich sample.As in the practical case, we also compared the PL spectra ofthe three samples at room temperature after long-term air exposurein air (∼6 months). Figures 4(a)–4(c) show the room temperaturespectra of the samples. All samples exhibit a PL emission peakaround 925 nm, which agrees with the typical room-temperatureemission wavelength of the InGaAs quantum wells. The PL signalsat room temperature decreased greatly compared with those mea-sured at 4 K (not shown here) due to the carrier thermal escapefrom the shallow QW. Remarkably, the intensity contrast betweenthe three samples is more significant at room temperature than at4 K. At room temperature, the Ga-rich and Se-terminated samplesshow intensities twice that of the As-rich sample. We attribute theenhanced contrast to the increased probability that carriers reachthe surface before being recombined in the QW. Although onlyphotogenerated carriers generated in the upper part of the QWhave a chance to reach the non-radiative recombination center atthe surfaces, carriers generated in the lower part of the QW canalso reach the surface due to the thermal escape. Therefore, thenegative impacts could be enhanced.We performed XPS measurements to understand the origin ofthe differences between the three samples qualitatively. Figure 5shows the Ga3d- and As3d-XPS spectra of the three samplesFIG. 3. Time dependent change in the integrated PL intensity of the threesamples after exposure to air for a certain period of time. The measurementswere made at 4 K.FIG. 4. PL spectra of three samples after being stored in air for 6 months. The spectra were obtained at room temperature.Journal ofApplied PhysicsARTICLE pubs.aip.org/aip/japJ. Appl. Phys. 137, 243102 (2025); doi: 10.1063/5.0274742 137, 243102-4© Author(s) 2025 27 June 2025 02:47:20https://doi.org/10.60893/figshare.jap.c.7847021https://pubs.aip.org/aip/japimmediately after preparation and after 14 days. The spectra werefitted with Ga-As and several oxide-related components. The sumintensities of the As-oxide and Ga-oxide components are plotted inFigs. 6(a) and 6(b), respectively. Just after removing the samplesinto the air (within 30 min), a significant amount of oxide hadalready formed in both the As-rich and Ga-rich samples [Figs. 5(a)and 5(c)]. As expected on the basis of the atomic structures of theinitial surfaces [Figs. 1(a) and 1(b)], more As (Ga) oxide is formedFIG. 5. As 3d and Ga 3d core-level spectra of the three samples. (a and c) right after preparation and (b and d) after exposure to air for 14 days.Journal ofApplied PhysicsARTICLE pubs.aip.org/aip/japJ. Appl. Phys. 137, 243102 (2025); doi: 10.1063/5.0274742 137, 243102-5© Author(s) 2025 27 June 2025 02:47:20https://pubs.aip.org/aip/japin the As-rich (Ga-rich) sample than in the Ga-rich (As-rich)sample, indicating that the structure and composition of the initialsurfaces strongly affect the oxide formation. Since the As-richsample exhibits weaker PL intensity, it is likely that the formationof As oxides is responsible for the degradation of the PL properties,in good agreement with our previous results for an S-terminatedGaAs surface.35In marked contrast with the results for As-rich and Ga-richsamples, no As-oxide components are detected in the spectrum of theSe-terminated sample measured just after preparation [Fig. 5(a), toppanel]. Since, as mentioned earlier, there are no As atoms in the firstfour layers of the Se-terminated surface [Fig. 1(c)], it is likely that Asatoms in deeper layers (>0.5 nm in depth) are not reached by the oxi-dation at this stage. In addition, the amount of Ga oxide is muchsmaller than that in the As-rich and Ga-rich samples, which is alsoclosely related to the atomic structure of the Se-terminated (2 × 1)surface, in which all the Ga atoms in surface layers are fourfold-coordinated and no Ga dangling bonds are present. These resultsconfirm that the Se-termination effectively suppresses the formationof both Ga and As oxides in the early stages of air exposure (<24 h),leading to less PL property degradation [Fig. 2(c)].After 14 days, the amount of both the As and Ga oxidesincreases in all the samples, as shown in Figs. 5(b) and 5(d). In par-ticular, the Se-terminated sample shows a more significant increasethan the As- and Ga-rich samples: the amount of Ga oxidebecomes almost the same as that of the other two samples andthe amount of As oxide becomes almost the same as that of theGa-rich sample. These results suggest that the effect of theSe-termination in suppressing oxide formation does not persistwith longer periods of air exposure.Since the oxidation occurs at the outermost layer of the sub-strate, more (less) As oxide is formed on the As-rich (As-deficient)surfaces in the initial stage of oxidation, as confirmed by XPS analy-sis [Figs. 5(a) and 5(c)]. Thus lower (higher) PL intensities forAs-rich (As-deficient) samples (Fig. 2) indicate that As oxide at thesurface has significant negative impacts on the PL properties in theearly stage of oxidation. On the other hand, during a longer air expo-sure (>1 day), the oxidation proceeds progressively from the surfacelayers into deeper layers, resulting in an increase in both As and Gaoxides in all the samples, as seen in Fig. 5, which is accompanied bythe degradation of the PL properties. With the Se-terminated sample,when the oxidation reaches As atoms in deeper layers (>0.5 nmdeep), the As atoms begin to be oxidized, leading to a delay in theonset of the PL degradation (1 day∼ 14 days).It has been reported that elemental As atoms are formed atthe interface between oxides and GaAs substrate, which is closelyrelated to the PL properties of GaAs.41,42 However, since it is verydifficult to detect the elemental As from an oxidized GaAs sampleusing XPS, we could not answer the question as to whether the pos-sible existence of elemental As influences the PL properties of oursamples. On the other hand, the present results clearly show thatAs oxide at the surface layers degrades the PL properties morestrongly than As oxide formed in deeper layers. We conclude thatpreparation of an As-deficient (Ga-rich) surface structure is effec-tive in improving the PL properties of a GaAs sample.IV. SUMMARY AND CONCLUSIONSWe investigated the PL properties of MBE-grown GaAs/InGaAs/GaAs(100) QW structures during oxidation under atmospheric condi-tions. The PL properties and the oxidation processes stronglydepend on the composition of the initial GaAs(100) surfaces: largeramounts of As oxide are formed in a sample with an As-richsurface of c(4 × 4)α, giving rise to a significant decrease in the PLintensity. On the other hand, samples with a Ga-rich (4 × 6)surface exhibit higher PL intensities, which could be ascribed to alesser amount of As oxide. While Se treatment is effective in delay-ing the onset of the oxidation and the resultant PL degradation, nosignificant difference from the Ga-rich (4 × 6) sample was observedafter 5 days exposure to air. We found that the simple preparationFIG. 6. The sum intensities of the (a) As-oxide and (b) Ga-oxide components of the three samples estimated from the XPS measurements. Just after removing thesamples into the air (within 30 min) and after 14 days.Journal ofApplied PhysicsARTICLE pubs.aip.org/aip/japJ. Appl. Phys. 137, 243102 (2025); doi: 10.1063/5.0274742 137, 243102-6© Author(s) 2025 27 June 2025 02:47:20https://pubs.aip.org/aip/japof As-deficient GaAs surfaces is effective in suppressing the degra-dation of the PL properties of buried QW structures even afterlong-term atmospheric exposure.SUPPLEMENTARY MATERIALSee the supplementary material for an additional figure of thelow-temperature PL spectrum with a logarithmic intensity scale,where each emission peak is identified.ACKNOWLEDGMENTSThis work was supported by the Innovative Science andTechnology Initiative for Security, Grant No. JPJ004596, ATLA,Japan.AUTHOR DECLARATIONSConflict of InterestThe authors have no conflicts to disclose.Author ContributionsZhao Ma: Conceptualization (equal); Data curation (equal);Investigation (equal); Methodology (equal); Validation (equal);Writing – original draft (equal); Writing – review & editing(equal). Takaaki Mano: Conceptualization (equal); Funding acqui-sition (equal); Methodology (equal); Project administration(equal); Resources (equal); Supervision (equal); Writing – review &editing (equal). Akihiro Ohtake: Conceptualization (equal); Datacuration (equal); Investigation (equal); Resources (equal);Supervision (equal); Validation (equal); Writing – review & editing(equal). Takashi Kuroda: Conceptualization (equal); Fundingacquisition (equal); Project administration (equal); Resources(equal); Supervision (equal); Writing – review & editing (equal).DATA AVAILABILITYThe data that support the findings of this study are availablefrom the corresponding authors upon reasonable request.REFERENCES1F. Lukeš, Surf. Sci. 30, 91 (1972).2W. E. Spicer, I. Lindau, P. E. Gregory, C. M. Garner, P. Pianetta, andP. W. Chye, J. Vac. Sci. Technol. 13, 780 (1976).3M. Scarrozza, G. Pourtois, M. Houssa, M. Heyns, and A. Stesmans, Phys. Rev.B 85, 195307 (2012).4W. E. Spicer, P. W. Chye, P. R. Skeath, C. Y. 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