Dependence of catalytic properties of indium implanted SiO2 thin films on the film-substrate temperature during indium ion implantation

Author(s):  
S. Yoshimura ◽  
K. Ikuse ◽  
M. Kiuchi ◽  
Y. Nishimoto ◽  
M. Yasuda ◽  
...  
1995 ◽  
Vol 385 ◽  
Author(s):  
M. Grant Norton ◽  
Wenbiao Jiang ◽  
J. Thomas Dickinson

ABSTRACTThin films of polytetrafluoroethylene have been formed by the pulsed-laser deposition technique. The structure of the films was found to be dependent upon the substrate temperature during deposition. At substrate temperatures from room temperature to 200°C the films were determined, by transmission electron microscopy and X-ray diffraction techniques, to be amorphous. Films formed at higher substrate temperatures were found to contain both amorphous and crystalline components. The data for the crystalline component is consistent with it being highly ordered with the long helical molecular chains aligned parallel to the film-substrate interface plane. The maximum amount of crystalline material occurred when the substrate temperature was close to the melting temperature of the polymer.


Author(s):  
O. Eibl ◽  
G. Gieres ◽  
H. Behner

The microstructure of high-Tc YBa2Cu3O7-X thin films deposited by DC-sputtering on SrTiO3 substrates was analysed by TEM. Films were either (i) deposited in the amorphous state at substrate temperatures < 450°C and crystallised by a heat treatment at 900°C (process 1) or (ii) deposited at around 740°C in the crystalline state (process 2). Cross sections were prepared for TEM analyses and are especially useful for studying film substrate interdiffusion (fig.1). Films deposited in process 1 were polycristalline and the grain size was approximately 200 nm. Films were porous and the size of voids was approximately 100 nm. Between the SrTiO3 substrate and the YBa2Cu3Ox film a densly grown crystalline intermediate layer approximately 150 nm thick covered the SrTiO3 substrate. EDX microanalyses showed that the layer consisted of Sr, Ba and Ti, however, did not contain Y and Cu. Crystallites of the layer were carefully tilted in the microscope and diffraction patterns were obtained in five different poles for every crystallite. These patterns were consistent with the phase (Ba1-XSrx)2TiO4. The intermediate layer was most likely formed during the annealing at 900°C. Its formation can be understood as a diffusion of Ba from the amorphously deposited film into the substrate and diffusion of Sr from the substrate into the film. Between the intermediate layer and the surface of the film the film consisted of YBa2Cu3O7-x grains. Films prepared in process 1 had Tc(R=0) close to 90 K, however, critical currents were as low as jc = 104A/cm2 at 77 K.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aziz Ahmed ◽  
Seungwoo Han

AbstractN-type bismuth telluride (Bi2Te3) thin films were prepared on an aluminum nitride (AlN)-coated stainless steel foil substrate to obtain optimal thermoelectric performance. The thermal co-evaporation method was adopted so that we could vary the thin film composition, enabling us to investigate the relationship between the film composition, microstructure, crystal preferred orientation and thermoelectric properties. The influence of the substrate temperature was also investigated by synthesizing two sets of thin film samples; in one set the substrate was kept at room temperature (RT) while in the other set the substrate was maintained at a high temperature, of 300 °C, during deposition. The samples deposited at RT were amorphous in the as-deposited state and therefore were annealed at 280 °C to promote crystallization and phase development. The electrical resistivity and Seebeck coefficient were measured and the results were interpreted. Both the transport properties and crystal structure were observed to be strongly affected by non-stoichiometry and the choice of substrate temperature. We observed columnar microstructures with hexagonal grains and a multi-oriented crystal structure for the thin films deposited at high substrate temperatures, whereas highly (00 l) textured thin films with columns consisting of in-plane layers were fabricated from the stoichiometric annealed thin film samples originally synthesized at RT. Special emphasis was placed on examining the nature of tellurium (Te) atom based structural defects and their influence on thin film properties. We report maximum power factor (PF) of 1.35 mW/m K2 for near-stoichiometric film deposited at high substrate temperature, which was the highest among all studied cases.


1998 ◽  
Vol 545 ◽  
Author(s):  
J. C. Caylor ◽  
A. M. Stacy ◽  
T. Sands ◽  
R. Gronsky

AbstractBulk skutterudite phases based on the CoAs3 structure have yielded compositions with a high thermoelectric figure-of-merit (“ZT”) through the use of doping and substitutional alloying. It is postulated that further enhancements in ZT may be attained in artificially structured skutterudites by engineering the microstructure to enhance carrier mobility while suppressing the phonon component of the thermal conductivity. In this work the growth and properties of singlephase CoSb3 and IrSb3 skutterudite thin films are reported. The films are synthesized by pulsed laser deposition (PLD) where the crystallinity can be controlled by the deposition temperature. Powder X-ray diffraction (PXRD), Transmission electron microscopy (TEM) and Rutherford- Back Scattering (RBS) were used to probe phase, structure, morphology and stoichiometry of the films as functions of growth parameters and substrate type. A substrate temperature of 250°C was found to be optimal for the deposition of the skutterudites from stoichiometric targets. Above this temperature the film is depleted of antimony due to its high vapor pressure eventually reaching a composition where the skutterudite structure is no longer stable. However, when films are grown from antimony-rich targets the substrate temperature can be increased to at least 350°C while maintaining the skutterudite phase. In addition, adhesion properties of the films are explored in terms of the growth mode and substrate interaction. Finally, preliminary room temperature electrical and thermal measurements are reported.


2008 ◽  
Vol 1111 ◽  
Author(s):  
Celine Lecerf ◽  
Philippe Marie ◽  
Cedric Frilay ◽  
Julien Cardin ◽  
Xavier Portier

AbstractPhotoluminescence activity was observed for neodymium-doped gallium oxide thin films prepared by radiofrequency magnetron co-sputtering. Structural and optical properties of as-grown and annealed films were studied and photoluminescence activity was especially investigated. The most intense lines were associated to the 4F3/2  4I9/2 and 4F3/2  4I11/2 electronic transitions of Nd3+. The effects of deposition and treatment parameters such as the substrate temperature, the post anneal treatment or the neodymium content in the films were particularly examined with the aim to reach the best luminescence efficiency.


Sign in / Sign up

Export Citation Format

Share Document