The Effects of Composition on the Spectral Loss Characteristics of SiGe Planar Waveguide Structures

1992 ◽  
Vol 281 ◽  
Author(s):  
Yang Zuoya ◽  
B. L. Weiss ◽  
G. Shao ◽  
F. Namavar
Keyword(s):  
Optical Properties ◽  
Planar Waveguide ◽  
Waveguide Structure ◽  
Propagation Loss ◽  
Band Edge ◽  
Optical Confinement ◽  
Structural And Optical Properties ◽  
Edge Absorption

ABSTRACTThe effect of the Si:Ge ratio in SiGe/Si heterostructures on the structural and optical properties of SiGe/Si planar waveguide are reported here for Ge concentrations from 1 to 33.6%. The high propagation loss at 1.15 pm is due to band edge absorption, which increases as the Ge concentration increases, while the loss at longer wavelengths (1.523 pm) increases with decreasing Si concentration, due to the reduced optical confinement of the waveguide structure.

Enhanced Properties of Porous GaN Prepared by UV Assisted Electrochemical Etching

2011 ◽  
Vol 364 ◽  
pp. 90-94 ◽  
Author(s):  
Mahmood Ainorkhilah ◽  
Mahmoud Ahmed Naser ◽  
Hassan Zainuriah ◽  
Fong Kwong Yam ◽  
Siti Khadijah Mohd Bakhori ◽  
...  
Keyword(s):  
Optical Properties ◽  
Stress Relaxation ◽  
Compressive Stress ◽  
Raman Spectra ◽  
Electrochemical Etching ◽  
Band Edge ◽  
Structural And Optical Properties ◽  
Sem Micrographs ◽  
Porous Layers ◽  
Enhanced Properties

The structural and optical properties of porous GaN films on sapphire (0001) prepared by UV assisted electrochemical etching were reported in this study. SEM micrographs indicated that the shapes of the pores for both porous samples are nearly hexagonal. As compared to the as-grown GaN films, porous layers exhibit a substantial photoluminescence (PL) intensity enhancement with red-shifted band-edge PL peaks associated with the relaxation of compressive stress. The shift of E2(high) to the lower frequency in Raman spectra of the porous GaN films further confirms such a stress relaxation.

The Effect of Buffer Layers in Mocvd Growth of Gan Film on 3C-SiC/Si Substrate

2000 ◽  
Vol 639 ◽  
Author(s):  
C. I. Park ◽  
J. H. Kang ◽  
K. C. Kim ◽  
K. Y. Lim ◽  
E.-K. Suh ◽  
...  
Keyword(s):  
Optical Properties ◽  
Surface Morphology ◽  
Buffer Layer ◽  
Buffer Layers ◽  
Band Edge ◽  
Band Edge Emission ◽  
Si Substrate ◽  
Structural And Optical Properties ◽  
Gan Film ◽  
Gan Buffer Layer

ABSTRACTThe growth of GaN films on Si substrates is very attractive work because of irreplaceable merits of Si wafer such as low cost, high surface quality, large area wafer availability, high conductivity and well-established processing techniques.In this work, we studied the effect of buffer layers to grow high quality GaN films on 3C- SiC/Si(111) substrates. GaN films were grown on 3C-SiC/Si(111) by metalorganic chemical vapor deposition (MOCVD) using various buffer layers (GaN, AlN, and superlattice). The surface morphology and structural and optical properties of GaN films were investigated with atomic force microscopy (AFM), x-ray diffraction (XRD), Raman spectroscopy, and Photoluminescence (PL), respectively. GaN films grown using superlattice buffer layer showed only c-oriented (0002) plane of GaN from the XRD analysis. Raman spectra showed that the E2 high mode agreed with the selection rule was well observed in all GaN films. The A1(TO) and E1(TO) mode were appeared for GaN grown without buffer layer, whereas the E1(TO) mode was additionally appeared in the GaN films grown with GaN buffer layer. In the PL spectra at low temperature, the peaks associated with band edge emission and donor-accepter pair (D0A0) were observed in GaN films grown without buffer layer or with GaN buffer layer and AlN buffer layer. GaN films grown with superlattice buffer layer showed band edge and very weak D0A0 emission. The root mean square (RMS) roughness of the GaN film grown on superlattice buffer layer was only 4.21 Å Our experimental results indicated that the buffer layer affects crucially the qualities of GaN films grown on the 3C-SiC/Si substrate. Superlattice buffer layer improved the surface morphology as well as structural and optical properties of GaN films.

Structural and Optical Properties of Cu2ZnSn(SxSe1–x)4 Thin Films

2018 ◽  
Vol 23 (3) ◽  
pp. 230-239
Author(s):  
E.P. Zaretskaya ◽  
◽  
V.F. Gremenok ◽  
A.V. Stanchik ◽  
A.N. Pyatlitski ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Structural And Optical Properties

Structural and optical properties of Tin Oxide and Indium doped SnO2 thin films deposited by thermal evaporation technique

2016 ◽  
Vol 12 (3) ◽  
pp. 4394-4399
Author(s):  
Sura Ali Noaman ◽  
Rashid Owaid Kadhim ◽  
Saleem Azara Hussain
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Tin Oxide ◽  
Thermal Evaporation ◽  
Pure Sno2 ◽  
X Ray Diffraction ◽  
Structural And Optical Properties ◽  
X Ray ◽  
Evaporation Technique ◽  
Sno2 Thin Films

Tin Oxide and Indium doped Tin Oxide (SnO2:In) thin films were deposited on glass and Silicon  substrates  by  thermal evaporation technique.  X-ray diffraction pattern of  pure SnO2 and SnO2:In thin films annealed at 650oC and the results showed  that the structure have tetragonal phase with preferred orientation in (110) plane. AFM studies showed an inhibition of grain growth with increase in indium concentration. SEM studies of pure  SnO2 and  Indium doped tin oxide (SnO2:In) ) thin films showed that the films with regular distribution of particles and they have spherical shape.  Optical properties such as  Transmission , optical band-gap have been measured and calculated.

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