Polarized and resonant Raman spectroscopy on single InAs nanowires

Abstract

We report polarized Raman scattering and resonant Raman scattering studies on single InAs nanowires. Polarized Raman experiments show that the highest scattering intensity is obtained when both the incident and analyzed light polarizations are perpendicular to the nanowire axis. InAs wurtzite optical modes are observed. The obtained wurtzite modes are consistent with the selection rules and also with the results of calculations using an extended rigid-ion model. Additional resonant Raman scattering experiments reveal a redshifted E 1 transition for InAs nanowires compared to the bulk zinc-blende InAs transition due to the dominance of the wurtzite phase in the nanowires. Ab initio calculations of the electronic band structure for wurtzite and zinc-blende InAs phases corroborate the observed values for the E 1 transitions.

Effects of stacking variations on the lattice dynamics of InAs nanowires

“…46 Furthermore, a recent resonant Raman study on WZ InAs nanowires shows a redshift of the E 1 energy transition of about 100 meV from the bulk value. 47 It is worth to note here, that the enhancement does not occur for both polarizations to the same extent (see Fig. 3 and Ref.…”

Morphology and composition of oxidized InAs nanowires studied by combined Raman spectroscopy and transmission electron microscopy

“…The spectra of the nonoxidized NW is identical to bulk InAs and contain one main peak at ∼216 cm −1 assigned to the InAs transverse optical (TO) phonon mode and a weak side-peak at 237 cm −1 assigned to the longitudinal optical (LO) mode. According to the Raman selection rules of the WZ crystal structure only the TO mode is allowed in this polarization configuration [26], however, the LO mode may appear due to crystal stacking faults in the NW [15]. As seen in the lowermost curve of figure 1(c) the oxidized NW shows a drastically different spectrum containing two high intensity peaks at 203 and 250 cm −1 which do not match any phonon energies of the InAs structure but rather the E g (TO) mode at 198 cm −1 and A 1g (LO) mode at 257 cm −1 of crystalline arsenic [27] which can form at the surfaces of InAs as a result of the reaction As 2 O 3 +2InAs→In 2 O 3 +4As as proposed in [28].…”

Electronic band structure of wurtzite GaP nanowires via temperature dependent resonance Raman spectroscopy

“…The dimensions of these wires are too large to exhibit electron/phonon confinement [1][2][3]. However, the modified crystal structure in such wires (in reference to corresponding bulk samples) indicates new possibilities in the realm of nanoscience and nanotechnology [4][5][6][7][8][9][10][11][12][13][14][15][16][17] It is now well established that NWs of III-V semiconductors can be grown in wurtzite (WZ) phase along their length, though the corresponding bulk materials are in zinc-blende (ZB) phase [5]. The indirect band gap in ZB phase [18] limits the application of the latter in optoelectronic device fabrication.…”