Ultra-thin Titanium Oxide Films on. Mo(112), Measured by XPS. SPECIMEN DESCRIPTION (Accession #00936) SPECIMEN DESCRIPTION (Accession #00938)

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1 Ultra-thin Titanium Oxide Films on Accession #s 00936, 00937,00938 Mo(112), Measured by XPS Technique: XPS Dheeraj Kumar, Ming Shu Chen, and David W. Goodman a ) Texas A&M University, Department of Chemistl)', College Station, Texas _Wl2 (Received 26 August 2005; accepted II August 2006; published 28 December 2007) 1\vo preparation methods were employed to grow a well-ordered ultra-thin titanium oxide film on Mo(J (2), The tirst method consisted of growing the films by direct deposition of Ti by chemical vapor deposition, followed by oxidation. Better film quality was obtained by the second method which involved deposition of Ti onto monolayer SiO/Mo( 112), as described in our prior work. By using x-ray photoelectron spectroscopy, Ti was detennined to be in + 3 oxidation state American Vacuum Societ)'. [DOl: / I] Keywords: photoemission; titanium oxide; tllin film PACS: Gh. 79,60.Dp Host Material: #00936: Mo(112) single crystal; #00937: Si0 2 thin film on MO(112); #00938: TiO, thin film on SiO,lMo(112) Instrument: Physical Electronics, Inc Multitechnique System Major Elements in Spectrum: Mo, Si, Ti, 0, C Minor Elements In Spectrum: none Printed Spectra: 7 Spectra in Electronic Record: 7 Spectral Category: comparison SPECIMEN DESCRIPTION (Accession #00936) Host Material: Mo(l12) single crystal CAS RegIstry #: Host MaterIal Characteristics: homogeneous; solid; single crystal; conductor: metal Chemical Name: molybdenum Host Composition: Mo Form: single-crystal Structure: (112) body-centered cubic lattice History & Significance: Molybdenum has been widely used to grow thin films such as MgO, Si0 2, etc. (Refs. 1-4). An Mo( (12) substrate was chosen because Mo(112)-C(2x2)-[Si0 4 J (Ref. I) and Mo(l12)-(8x2)-TiO x (Refs. 2, 4) films can he grown on this substrate. As Received Condition: Mo(l12) was cut and polished to render (I 12) facets on hoth faccs of the single crystal. It is I em in diameter and J rom in thickness, and stored at room temperature. Analyzed Region: same as host material Ex Situ Preparation/Mounting: The as-prepared sample was mountcd using Ta wire spot-welded to the outside rim of the crystal. A thermocouple (W/5 wt % Re)/(W/26 wt % Re) was spot-welded lo thc back of the crystal. In Situ Preparation: ion sputter cleaning, oxidation at 1200 K, annealing to K Charge Control: The metallic Mo(J 12) sample was grounded. Temp. During Analysis: 300 K Pressure During Analysis: <6.5X 1Q-8 Pa SPECIMEN DESCRIPTION (Accession #00937) Host Malerial: Si0 2 thin film on Mo( 112) Host Material Characteristics: homogeneous; solid; polycrystal line; conductor; inorganic compound; thin film Chemical Name: silicon dioxide Source: thennally grown Si0 2 IAuthor to whom correspondence should be addressed. Host Composition: Si0 2 Form: thin film Structure: C(2x2)-[Si0 2 ]JMo(l12) I monolayer thick History & Significance: A well-ordered ultra-thin silica 1ilm is used to grow a (8x2)-TiOx film As Received Condition: sample should be prepared in situ in UHV Analyzed Region: same as host material Ex Situ Preparation/Mounting: prior to in situ preparation of Si0 2 thin film, the Mo(L 12) substrate was cleaned as described for Accession # fn Situ Preparation: Lcss than one monolayer Si was depositcd onto Mo(l12)-p(2x3)-0 surf,tce and oxidized at 800 K in I X Torr O 2 for 5.0 min. followed by annealing to 1200 K for another 5.0 min. This procedure was repeated until the desired thickness was obtained. Charge Control: The thin film is I ML thick and is conducting. TIle substrate Mo(112) sample was grounded. Temp. During Analysis: 300 K Pressure During Analysis: <6.5x 10-8 Pa SPECIMEN DESCRIPTION (Accession #00938) Host Material: Ti0 2 thin film on Si0 2 /Mo( 112) Host Material Characteristics: homogeneous; solid; polycrystalline: conductor; inorganic compound; thin film Chemical Name: titanium oxide Source: thermally grown Ti0 2 thin film Host Composition: Ti0 2 Form: thin film Structure: close packed structure As Received Condition: sample should be prepared in situ in UHV Analyzed Region: same as host material Ex Situ Preparation/Mounting: prior to in situ preparation of 5i0 2 thin film, the Mo(J 12) substrate was cleaned as described for Accession # In Situ Preparation: ML Ti was deposited onto a thin Si0 2 Surface Science Spectra, Vol. 14, American Vacuum Sociely 1

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