Raman spectroscopic determination of hole concentration in undoped GaAsBi. (27th November 2018)

• Record Type: Journal Article
• Authors: Zhu, Sixin; Qiu, Weiyang; Wang, Han; Lin, Tie; Chen, Pingping; Wang, Xingjun
• Is Part Of: Semiconductor science and technology. Volume 34:Number 1(2019)
• Publication Date: 2018-11-27
• Subjects: GaAsBi -- Raman spectroscopy -- LO-phonon-plasmon–modes -- Hole density -- Hall measurements; Semiconductors -- Periodicals; 621.38152
• DOI: 10.1088/1361-6641/aaef02
• Languages: English
• ISSNs: 0268-1242

Abstract

Abstract: Raman spectra of undoped GaAs1−x Bix (0 < x < 0.037) grown on GaAs by molecular beam epitaxy were investigated. With an increase of Bi component, we find that the longitudinal optical phonon-hole-plasmon-coupled (LOPC) mode first appears in the vicinity of the unscreened longitudinal optical (ULO) phonon frequency, and then shifts towards the transverse optical (TO) phonon frequency. A new vibrational mode (∼287 cm −1 ) between the TO and the ULO phonons was verified by use of low temperature polarized Raman measurement and the corresponding scattering intensities are found to be linearly proportional to the composition of Bi in GaAsBi. The hole concentrations determined by using the LOPC/ULO Raman intensities ratio increase from ∼6.5 × 10 16 to ∼2.8 × 10 17 cm −3 with increased Bi content and the measured results are in agreement with Hall measurements. Furthermore, the influence of excitation laser power on the estimation of the hole densities is discussed with the help of power dependent Raman spectroscopy.