Surface optical Raman modes in InN nanostructures

Abstract

Raman spectroscopic investigations are carried out on one-dimensional nanostructures of InN, such as nanowires and nanobelts synthesized by chemical vapor deposition. In addition to the optical phonons allowed by symmetry; A 1, E 1 and E 2 (high) modes, two additional Raman peaks are observed around 528 cm -1 and 560 cm -1 for these nanostructures. Calculations for the frequencies of surface optical (SO) phonon modes in InN nanostructures yield values close to those of the new Raman modes. A possible reason for large intensities for SO modes in these nanostructures is also discussed.

Raman spectroscopy of GaP/GaNP core/shell nanowires

“…3) downshifts with increasing the dielectric constant of the surrounding media, whereas the positions of the other modes remain constant. This behaviour is typical for the so-called surface optical (SO) phonons 21,[38][39][40] that can be activated by breakdown of translational symmetry at surfaces. The wavevector of the corresponding perturbing potential could be determined based on an analysis of SO dispersion.…”

“…The wavelength k SO ¼ 2p=q SO corresponding to the perturbation of the surface potential can then be estimated as being $115 nm. Several mechanisms were proposed 21,39,40 to explain the SO activation in NWs, including surface roughness, saw tooth faceting on the NW sidewall, or a diameter modulation along the NW length on the scale of k SO . None of these mechanisms, however, seem to be relevant to the studied structures.…”

Growth of InN quantum dots to nanorods: a competition between nucleation and growth rates

“…S1). Nanorods are also shown in the TEM studies ( The presence of O at 700 o C may be correlated to its associated dissociation of InN and reoxidation at high growth temperature [7,8] [25,26]. Among these, A 1 and E 1 modes are polar in nature; because of this reason these modes are further split into longitudinal optic (LO) and transverse optic (TO) components.…”

Surface Optical Modes in Semiconductor Nanowires

“…An optical mode of one-dimensional nanostructures of InN, such as nanowires and nanobelts grown by chemical vapor deposition, has been studied in our earliest report (Sahoo et al, 2008). Typical Raman spectra of nanowires and nanobelts are shown in figures 10(a) and (b), respectively and SO phonons modes have been reported taking into consideration of cylindrical geometry to both.…”