Electronic Raman scattering and the second-order Raman spectra of the n-type SiC

Abstract

The Raman scattering spectra of the nitrogen doped n-SiC is studied. The theoretical line shape analysis indicates that, compared with 4H-SiC, the shift of the LO phonon-plasma coupled mode in 6H-SiC with free carrier concentration is smaller. From the electronic Raman spectra, which were obtained with laser excitation at 5145nm, there are four spectral lines in 6H-SiC and two lines in 4H-SiC, which correspond to the 1s(A1) to 1s(E) valley orbit transitions at the inequivalent k site. The explanation of the high-frequency signals of 6303 and 635 cm-1 is that they are velated with transitions at active deep level of defect. Finally, the second-order Raman features of 6H- and 4H-SiC are identified using the selection rules for second-order scattering in wurtzite structure.

Propagation and Interaction of Ion-Acoustic Solitary Waves in a Two-Dimensional Plasma Consisting of Isothermal Electrons and Hot Ions

“…A number of authors have studied ion-acoustic solitons in different plasma systems. [7,8] The excitation, propagation, and interaction of solitary waves are important issues in theoretical studies. We know that one of the striking properties of solitons is their asymptotic preservation of form when they undergo a collision, as first remarked by Zabusky and Kruskal.…”