A SYNCHROTRON RADIATION STUDY OF THE FORMATION OF CuxSey AND NaxCuySez THIN FILMS ON Cu SUBSTRATES: Cl2-INDUCED OUT-DIFFUSION OF Na

2000 ◽  
Vol 07 (03) ◽  
pp. 235-242 ◽  
Author(s):  
V. SALTAS ◽  
C. A. PAPAGEORGOPOULOS ◽  
D. C. PAPAGEORGOPOULOS ◽  
D. TONTI ◽  
C. PETTENKOFER ◽  
...  
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Synchrotron Radiation ◽  
Copper Selenide ◽  
Photoemission Spectroscopy ◽  
Radiation Study ◽  
Cu Substrates ◽  
Compound Exposure ◽  
Selenide Film

In this paper we study the growth of Cu x Se y and Na x Cu y Se z thin films on polycrystalline Cu substrates. The investigation took place in situ by means of photoemission spectroscopy with synchrotron radiation, in UHV. Deposition of elemental Se with a dense flux on a polycrystalline Cu substrate at RT and subsequent heating to 100°C causes the formation of a thick Cu 2-x Se film (with x equal or very close to zero). A phase transition of this copper selenide occurs by annealing at 200°C. Deposited Na on the Cu 2-x Se film is diffused into the bulk, resulting in the formation of a Na x Cu y Se z compound. Exposure to Cl 2 at 120°C causes the out-diffusion of Na to the surface, where NaCl is formed. The Na diffusion in and out of the copper selenide film is analogous to alkali intercalation–deintercalation from TX 2 layer compounds.

Combinatorial in situ Growth-and-Analysis with Synchrotron Radiation of Thin Films for Oxide Electronics

2007 ◽  
Author(s):  
M. Oshima ◽  
H. Kumigashira ◽  
K. Horiba ◽  
T. Ohnishi ◽  
M. Lippmaa ◽  
...  
Keyword(s):  
Thin Films ◽  
Synchrotron Radiation ◽  
In Situ Growth ◽  
Oxide Electronics

Effect of Deposition Conditions on Intrinsic Stress, Phase Transformation and Stress Relaxation in Tantalum Thin Films

1991 ◽  
Vol 239 ◽  
Author(s):  
A. Mutscheller ◽  
L. A. Clevenger ◽  
J.M.E. Harper ◽  
C. Cabrai ◽  
K. Barmakt
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Phase Transformation ◽  
Stress Relaxation ◽  
Compressive Stress ◽  
Stress Relief ◽  
Beta Phase ◽  
Alpha Phase ◽  
Intrinsic Stress

AbstractWe demonstrate that the high temperature polymorphic tantalum phase transition from the tetragonal beta phase to the cubic alpha phase causes complete stress relaxation and a large decrease in the resistance of tantalum thin films. 100 nm beta tantalum thin films were deposited onto thermally oxidized <100> silicon wafers by dc magnetron sputtering with argon. In situ stress and resistance at temperature were measured during temperature-ramped annealing in purified He. Upon heating, films that were initially compressively stressed showed increasing compressive stress due to thermo-elastic deformation from 25 to 550°C, slight stress relief due to plastic deformation from 550 to 700°C and complete stress relief due to the beta to alpha phase transformation at approximately 700–800°C. Incomplete compressive stress relaxation was observed at high temperatures if the film was initially deposited in the alpha phase or if the beta phase did not completely transform into alpha by 800°C. This incomplete beta to alpha phase transition was most commonly observed on samples that had radio frequency substrate bias greater than -100 V. We conclude that the main stress relief mechanism for tantalum thin films is the beta to alpha phase transformation that occurs at 700 to 800°C.

Vibrational and Electronic Properties of RbC60 Thin Films

1994 ◽  
Vol 359 ◽  
Author(s):  
G.P. Lopinski ◽  
M.G. Mitch ◽  
J.R. Fox ◽  
J.S. Lannin
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Electronic States ◽  
Orthorhombic Phase ◽  
Low Energy ◽  
Polymer Model ◽  
In Situ Raman ◽  
Intramolecular Vibrations ◽  
Two Phases

ABSTRACTIn situ Raman scattering, UPS and HREELS measurements have been used to study the fcc to orthorhombic phase transition in RbC60 thin films. Large changes in the Raman spectra are interpreted in terms of increased interfullerene coupling in the orthorhombic phase. However, the data do not support the proposed polymer model for this phase. Photoemission measurements indicate only small differences in the electronic states between the two phases in contrast with photopolymerized C60 where additional states are observed. Low energy metallic-like excitations and screening of intramolecular vibrations are observed in HREELS.

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