Interfacial Roughness in GaAs/A1GaAs Multilayers: Influence of Controlled Impurity Addition

1994 ◽  
Vol 332 ◽  
Author(s):  
S. Nayak ◽  
J.M. Redwing ◽  
T.F. Kuech ◽  
D.E. Savage ◽  
M.G. Lagally
Keyword(s):  
Atomic Force Microscopy ◽  
Optical Properties ◽  
Correlation Length ◽  
Interfacial Structure ◽  
X Ray Diffraction ◽  
Electrical And Optical Properties ◽  
Interfacial Roughness ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force

Impurities at heterointerfaces can alter the interfacial structure resulting in changes in physical, electrical and optical properties. We present a study of the interfacial roughness of GaAs/A1xGa1-xAs superlattices which were grown using controlled addition of oxygen at the interface. The interfacial properties were characterized by x-ray diffraction. The morphology of the surface was determined by Atomic Force Microscopy (AFM). X-ray diffraction measurements, both θ-2θ and rocking curves, were used to analyze the correlated and uncorrelated component of the interfacial roughness. A strong difference in the interfacial roughness was observed depending on whether the intentional oxygen incorporation occurred at the GaAs-to-A1GaAs interface or at both interfaces. When oxygen is incorporated at both interfaces, the x- ray reflectivity of the superlattice is decreased considerably resulting from a much higher interfacial roughness. The substrate miscut has a significant effect on RMS roughness, correlated roughness and its correlation length when oxygen is incorporated at the GaAs-to-A1xGa1-xAs interface.

scholarly journals Study of Structural and Optical Properties of Zinc Oxide Rods Grown on Glasses by Chemical Spray Pyrolysis

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Erdal Sonmez ◽  
Serdar Aydin ◽  
Mehmet Yilmaz ◽  
Mustafa Tolga Yurtcan ◽  
Tevhit Karacali ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Atomic Force Microscopy ◽  
Optical Properties ◽  
Spray Pyrolysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Scanning Electron

We have investigated morphological and optical properties of zinc oxide rods. Highly structured ZnO layers comprising with well-shaped hexagonal rods were prepared by spray pyrolysis deposition of zinc chloride aqueous solutions at ~550∘C. The rods were characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy, photoluminescence, and ultraviolet and visible absorption spectroscopy measurements. The deposition of the 0.1 mol/L solution at ~550∘C resulted in crystals with a diameter of 400–1000 nm and length of 500–2000 nm. Sharp near-band edge emission peaks, centered at 3844 and 3680 Å, dominated the PL spectra of ZnO at 300 K and 6.2 K, respectively. In addition to this, absorption coefficient was determined by absorption measurement. X-ray diffraction, scanning electron microscopy and atomic force microscopy, results suggest that ZnO rods, prepared by spray pyrolysis, have high crystalline quality. This is desirable in nanotechnology applications.

Nanocrystalline Solutions as Precursors to The Spray Deposition of Cdte Thin Films

1995 ◽  
Vol 382 ◽  
Author(s):  
Martin Pehnt ◽  
Douglas L. Schulz ◽  
Calvin J. Curtis ◽  
Helio R. Moutinho ◽  
Amy Swartzlander ◽  
...  
Keyword(s):  
Thin Films ◽  
Atomic Force Microscopy ◽  
Grain Size ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Cdte Nanoparticles ◽  
Atomic Force ◽  
Vis Spectroscopy ◽  
Cdte Thin Films

ABSTRACTIn this article we report the first nanoparticle-derived route to smooth, dense, phase-pure CdTe thin films. Capped CdTe nanoparticles were prepared by injection of a mixture of Cd(CH3)2, (n-C8H17)3 PTe and (n-C8H17)3P into (n-C8H17)3PO at elevated temperatures. The resultant nanoparticles 32-45 Å in diameter were characterized by x-ray diffraction, UV-Vis spectroscopy, transmission electron microscopy, thermogravimetric analysis and energy dispersive x-ray spectroscopy. CdTe thin film deposition was accomplished by dissolving CdTe nanoparticles in butanol and then spraying the solution onto SnO2-coated glass substrates at variable susceptor temperatures. Smooth and dense CdTe thin films were obtained using growth temperatures approximately 200 °C less than conventional spray pyrolysis approaches. CdTe films were characterized by x-ray diffraction, UV-Vis spectroscopy, atomic force microscopy, and Auger electron spectroscopy. An increase in crystallinity and average grain size as determined by x-ray diffraction was noted as growth temperature was increased from 240 to 300 °C. This temperature dependence of film grain size was further confirmed by atomic force microscopy with no remnant nanocrystalline morphological features detected. UV-Vis characterization of the CdTe thin films revealed a gradual decrease of the band gap (i.e., elimination of nanocrystalline CdTe phase) as the growth temperature was increased with bulk CdTe optical properties observed for films grown at 300 °C.

Characterization of X-ray irradiated graphene oxide coatings using X-ray diffraction, X-ray photoelectron spectroscopy, and atomic force microscopy

2013 ◽  
Vol 28 (2) ◽  
pp. 68-71 ◽  
Author(s):  
Thomas N. Blanton ◽  
Debasis Majumdar
Keyword(s):  
Atomic Force Microscopy ◽  
Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
High Energy ◽  
X Ray Diffraction ◽  
Carbon Phase ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After

In an effort to study an alternative approach to make graphene from graphene oxide (GO), exposure of GO to high-energy X-ray radiation has been performed. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) have been used to characterize GO before and after irradiation. Results indicate that GO exposed to high-energy radiation is converted to an amorphous carbon phase that is conductive.

Effect of ultra-thin Cu underlayer on the magnetic properties of Ni80Fe50 / Fe50Mn50 films

1999 ◽  
Vol 562 ◽  
Author(s):  
C. Liu ◽  
L. Shen ◽  
H. Jiang ◽  
D. Yang ◽  
G. Wu ◽  
...  
Keyword(s):  
Thin Film ◽  
Atomic Force Microscopy ◽  
Exchange Bias ◽  
Film Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Maximum Value ◽  
Film Roughness

ABSTRACTThe Ni80Fe20/Fe50Mn50,thin film system exhibits exchange bias behavior. Here a systematic study of the effect of atomic-scale thin film roughness on coercivity and exchange bias is presented. Cu (t) / Ta (100 Å) / Ni80Fe20 (100 Å) / Fe50Mno50 (200 Å) / Ta (200 Å) with variable thickness, t, of the Cu underlayer were DC sputtered on Si (100) substrates. The Cu underlayer defines the initial roughness that is transferred to the film material since the film grows conformal to the initial morphology. Atomic Force Microscopy and X-ray diffraction were used to study the morphology and texture of the films. Morphological characterization is then correlated with magnetometer measurements. Atomic Force Microscopy shows that the root mean square value of the film roughness exhibits a maximum of 2.5 Å at t = 2.4 Å. X-ray diffraction spectra show the films are polycrystalline with fcc (111) texture and the Fe50Mn50 (111) peak intensity decreases monotonically with increasing Cu thickness, t. Without a Cu underlayer, the values of the coercivity and loop shift are, Hc = 12 Oe and Hp = 56 Oe, respectively. Both the coercivity and loop shift change with Cu underlayer thickness. The coercivity reaches a maximum value of Hc= 36 Oe at t = 4 Å. The loop shift exhibits an initial increase with t, reaches a maximum value of HP = 107 Oe at t = 2.4 Å, followed by a decrease with greater Cu thickness. These results show that a tiny increase in the film roughness has a huge effect on the exchange bias magnitude.

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