The Sputter Deposition and Characterisation of High Quality Single Crystal Mo Thin Films

1990 ◽  
Vol 202 ◽  
Author(s):  
R. E. Somekh ◽  
D. Van Vechten ◽  
M. G. Blamire ◽  
D. M. Tricker ◽  
Z. H. Barber ◽  
...  
Keyword(s):  
Room Temperature ◽  
Gamma Ray ◽  
Xrd Analysis ◽  
Sputter Deposition ◽  
Superconducting Transition ◽  
Conductivity Measurements ◽  
High Quality ◽  
Temperature Resistance ◽  
Sapphire Substrates ◽  
Gamma Ray Detector

ABSTRACTWe report on the epitaxial growth of superconducting molybdenum films on sapphire substrates. These films are to be etched into arrays of isolated cylinders, each 1–5μm in diameter. When placed in a magnetic field and biased at 0.95 Tc(H), the flux movement associated with their bolometric response to the energy deposited when radiation is absorbed will provide the basis of a gamma-ray detector.The films were prepared by UHV sputter deposition at temperatures between 650° and 840°C. Besides standard XRD analysis the films were examined by TEM. An epitaxy orientation relationship with sapphire was found similar to that observed for niobium. Electrical conductivity measurements were made as a function of temperature down to Tc, the superconducting transition temperature, which ranged from below 0.35K to above 0.8K for films with a high room temperature resistance ratio (e.g. 300 in a 0.9pjn thick film). Results from a range of films will be presented and their Tc’s discussed.

High-Mobility Ga-Polarity GaN achieved by NH3-MBE

2002 ◽  
Vol 743 ◽  
Author(s):  
J. X. Wang ◽  
X. L. Wang ◽  
D. Z. Sun ◽  
J. M. Li ◽  
Y. P. Zeng ◽  
...  
Keyword(s):  
Room Temperature ◽  
High Mobility ◽  
Radio Frequency Plasma ◽  
Chemical Solution ◽  
High Quality ◽  
Sapphire Substrates ◽  
Best Value ◽  
Frequency Plasma ◽  
Surface Examination

ABSTRACTGaN epilayers were grown on (0001) sapphire substrates by NH3-MBE and RF-MBE (radio frequency plasma). The polarities of the epilayers were investigated by in-situ RHEED, chemical solution etching and AFM surface examination. By using a RF-MBE grown GaN layer as template to deposit GaN epilayer by NH3-MBE method, we found that not only Ga-polarity GaN films were repeatedly obtained, but also the electron mobility of these Ga-polarity films was significantly improved with a best value of 290 cm2/V.s at room temperature. Experimental results show it is an easy and stable way for growth of high quality Ga-polarity GaN films.

A silicon x- and gamma-ray detector for room temperature and low voltage operation

1982 ◽  
Vol 193 (1-2) ◽  
pp. 63-67 ◽  
Author(s):  
Massaya Yabe ◽  
Noritada Sato ◽  
Hiroshi Kamijo ◽  
Toshiaki Takechi ◽  
Fumio Shiraishi
Keyword(s):  
Room Temperature ◽  
Gamma Ray ◽  
Low Voltage ◽  
Low Voltage Operation ◽  
Gamma Ray Detector

Excitons bound to structural defects in GaN

2001 ◽  
Vol 693 ◽  
Author(s):  
M. A. Reshchikov ◽  
D. Huang ◽  
F. Yun ◽  
H. Morkoç ◽  
R. J. Molnar ◽  
...  
Keyword(s):  
Molecular Beam Epitaxy ◽  
Room Temperature ◽  
Molecular Beam ◽  
Structural Defects ◽  
Excitation Density ◽  
High Quality ◽  
Pl Spectra ◽  
Sapphire Substrates ◽  
Uv Illumination ◽  
Increasing Temperature

AbstractWe analyzed the photoluminescence (PL) spectra of undoped GaN films grown by molecular beam epitaxy on sapphire substrates. While the PL spectra from high-quality samples contain free and bound exciton peaks only, the spectra from some samples involve sharp unidentified peaks in the energy range of 3.0 – 3.45 eV, specifically at 3.21, 3.32, 3.36, and 3.42 eV. We attribute these peaks to excitons bound to defects because of the linear and sometimes superlinear increase in their intensity with excitation density without saturation up to 100 W/cm2. With increasing temperature these peaks quench in a well-known fashion similar to that for excitons. In order to relate the observed peaks to the structural defects, we etched selected samples in hot H3PO4 acid or, alternatively, with photo-electrochemical (PEC) etching at room temperature in the presence of UV-illumination in a dilute KOH solution. In the former case the dislocations were etched leaving etched pits on the surface, while in the latter case the dislocations remained unetched due to a deficit of photogenerated holes at dislocation sites. We found that the 3.42 eV peak disappeared after both hot wet and PEC etching suggesting that the associated defect is at the GaN surface. Peaks at 3.21 and 3.36 eV could be enhanced greatly by PEC etching, which were correlated to bulk dislocations.

Epitaxial Growth of Nb Films and Nb/Cu Bilayers on A12O3 Substrates by DC Magnetron Sputtering

1998 ◽  
Vol 528 ◽  
Author(s):  
R. Loloee ◽  
M.A. Crimp ◽  
W. Zhu ◽  
W.P. Pratt
Keyword(s):  
Electron Microscopy ◽  
Sputter Deposition ◽  
Dc Magnetron Sputtering ◽  
High Quality ◽  
Cu Films ◽  
Force Microscopy ◽  
Sputtered Films ◽  
Sapphire Substrates ◽  
Atomic Force ◽  
Transmission Electron

AbstractEpitaxial single crystal Nb films have been grown by sputter deposition on (1 1 2 0) sapphire substrates. Subsequently, high quality epitaxial Cu films, with two orientation variants, have been grown onto the epitaxial Nb films. The sputtered films have been characterized using atomic force microscopy, electron backscattered patterns, and conventional transmission electron microscopy.

Effect of in Concentration on the Optical Lattice Vibrations in Quaternary AlxInyGa1-x-yN Alloys

2012 ◽  
Vol 501 ◽  
pp. 281-285
Author(s):  
A.I. Aljameel ◽  
H. Abu Hassan ◽  
S.S Ng
Keyword(s):  
Mole Fraction ◽  
Optical Lattice ◽  
Room Temperature ◽  
Molecular Beam ◽  
Buffer Layers ◽  
Lattice Vibrations ◽  
High Quality ◽  
Long Wavelength ◽  
Sapphire Substrates ◽  
Mode Behavior

Fourier transform infrared (FTIR) spectroscopy has been utilized to measure long-wavelength optical lattice vibrations of high-quality quaternary AlxlnyGa1-x-yN thin films at room temperature. The AlxlnyGa1-x-yN films were grown on c-plane (0001) sapphire substrates with AlN as buffer layers using plasma assisted molecular beam epitaxy (PA-MBE) technique with indium (In) mole fraction y = 0.0 to 0.10 and constant aluminium (Al) mole fraction x = 0.06. The experimental results indicated that the AlxlnyGa1-x-yN alloys had two-mode behavior, for the A1 (LO) and E1 (TO) modes.

Sign in / Sign up

Export Citation Format

Share Document