Observation of the forbidden doublet optical phonon in Raman spectra of strained Si for stress analysis

2010 ◽  
Vol 97 (4) ◽  
pp. 041915 ◽  
Author(s):  
Vladimir Poborchii ◽  
Tetsuya Tada ◽  
Toshihiko Kanayama
Keyword(s):  
Stress Analysis ◽  
Raman Spectra ◽  
Optical Phonon ◽  
Strained Si

Nondestructive Characterizations of Au-Catalyzed GaAs Nanowires on GaAs(111)B Substrates via Identifications of 1st Order Optical Phonon Modes Using μ-Raman Spectroscopy

2020 ◽  
Vol 20 (7) ◽  
pp. 4358-4363
Author(s):  
Jeung Hun Park ◽  
Richard S. Kim ◽  
Se-Jeong Park ◽  
Gye-Choon Park ◽  
Choong-Heui Chung
Keyword(s):  
Raman Spectroscopy ◽  
Dose Rate ◽  
Raman Spectra ◽  
Optical Phonon ◽  
Longitudinal Optical ◽  
Transverse Optical ◽  
Longitudinal Optical Phonon ◽  
Phonon Modes ◽  
Gaas Nanowires ◽  
Beam Dose

We report the relation between the catalyst patterning conditions and the intensity of the 1st order Raman active modes in Au-catalyzed GaAs nanowire bundles. We fabricated e-beam lithographically Au-patterned GaAs(111)B substrates by varying the patterning conditions (e-beam dose rate, dot-size and interdot-spacings), and grew GaAs nanowires via vapor–liquid–solid process using a solid-source molecular beam epitaxy. To understand the effects of the substrate preparation conditions and resulting morphologies on the optical characteristics of 1st order transverse optical and longitudinal optical phonon modes of GaAs, we characterized the nanowire bundles using complementary μ-Raman spectroscopy and scanning electron microscopy as a function of the e-beam dose rate (145–595 μC/cm2), inter-dot spacing (100 and 150 nm) and pattern size (100 and 150 nm). Ensembles of single crystalline GaAs nanowires covered with different Au-thickness exhibit a downshift and asymmetric broadening of the 1st order transverse optical and longitudinal optical phonon peaks relative to GaAs bulk modes. We also showed that the sensitivity of a downshift and broadening of Raman spectra are directly related to morphological and surface coverage variations in as-grown nanowires. We observed clear increases of the transverse optical and longitudinal optical intensity as well as the relatively higher peak shift and broadening of Raman spectra from the 100 nm patterning in response to the dose rate change. Strong dependence of Raman spectra of the nanowire bundles on the e-beam dose rate changes are attributed to the variations in spatial density, size, shape and random growth orientation of the wires. We have shown that the identification of the changes in GaAs longitudinal optical and Arsenic anti-site peaks is good indicators to characterize the quality of as-grown GaAs nanowires. Our finding confirms the utilization of Raman spectroscopy as a powerful tool for characterizing chemical, structural, and morphological information of as-grown nanowires within the supporting substrate.

Theory of Hydrogen Complexes in Si

1990 ◽  
Vol 209 ◽  
Author(s):  
S. B. Zhang ◽  
W. B. Jackson
Keyword(s):  
Binding Energy ◽  
Raman Spectra ◽  
Experimental Results ◽  
Lattice Expansion ◽  
Strained Si ◽  
Amorphous Si ◽  
Gap States ◽  
Hydrogenated Amorphous ◽  
And Diffusion ◽  
Strained Bonds

ABSTRACTThe predominance of Si-H bonding and the origin of {111} platelets in hydrogenated Si remain important unsolvedproblems in the study of H in Si.Recent theoretical and experimental results indicate that H predominately enters the Si network in pairs. A promising diatomic H configuration consists of a bond centered H closely associated with an antibonding centered H. In this work, we show that adjacent diatomic H pairs have a binding energy of 0.2 eV/2H. The binding originates from relaxation of strained Si-Si backbonds. Further clustering of the H pairs eliminates all strained bonds, forming a hydrogenated platelet oriented along the {111} plane. The binding energy of 3.95 eV/2H for the platelet is 0.15 eV lower than that for interstitial H2 molecules in c-Si. Lattice expansion makes the platelets energetically more competitivewith the lowest energy Si-H bonding confi gration at hydrogenated Si (111) surfaces. These higher level complexes explainthe formation of platelets, Raman spectra, and absence of gap states in hydrogenated c- Si as well as the clustered phaseseen in NMR and of H evolution and diffusion in hydrogenated amorphous Si.

Effect of defects on optical phonon Raman spectra in SiC nanorods

1999 ◽  
Vol 111 (11) ◽  
pp. 647-651 ◽  
Author(s):  
Shu-Lin Zhang ◽  
Bang-Fen Zhu ◽  
Fuming Huang ◽  
Yan Yan ◽  
Er-yi Shang ◽  
...  
Keyword(s):  
Raman Spectra ◽  
Optical Phonon
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