Phonon mode study of near-lattice-matched InxGa1−xAs using micro-Raman spectroscopy

Abstract

We identify the four allowable phonon modes in InxGa1−xAs on InP:InAs-like transverse optical (TO) (225±2 cm−1), InAs-like longitudinal optical (LO) (233±1 cm−1), GaAs-like TO (255±2 cm−1), and GaAs-like LO (269±1 cm−1), using the selectivity of first-order Raman scattering off the (100) normal surface and the (011) cleaved plane and detailed line-shape analysis employing a sequential simplex optimization procedure. Raman scattering off the (011) cleaved plane was achieved for the first time in thin-film InGaAs using microprobing capabilities (∼1 μm). We also identify another phonon mode R* at 244 cm−1 which is attributed to an alloy disorder mode in these films. For the five identified phonon modes, a linear relationship between the Raman frequencies and composition determined from x-ray diffraction was determined for near-lattice-matched conditions (0.42<1−x<0.52).

Raman scattering study of LO phonon–plasmon coupled modes in p-type InGaAs

“…Deformation-potential and electro-optic scattering mechanisms are allowed in this configuration, for which only the LO modes are symmetry-allowed. The spectrum of the sample with the lowest doping (A) resembles closely that of unintentionally doped (N e $ 10 15 cm À3 ) In 0.53 Ga 0.47 As previously reported [17]. The spectrum is dominated by an intense peak close to the GaAs-like LO phonon frequency.…”

“…This peak is broader than the GaAs-like LO phonon mode of In 0.53 Ga 0.47 As and displays a slight asymmetric broadening towards the high energy side, both of which are indicative of coupling with the hole plasma. The Raman spectrum of undoped In 0.53 Ga 0.47 As shows a broad mode labeled R Ã at $ 244 cm À1 that was assigned to a disorder mode [17]. The contributions of both the R Ã mode and of the GaAs-like LO phonon mode from the surface depletion region were estimated from a four-Lorentzian fit to the spectra, and are plotted in Fig.…”

Study of the electrical activation of Si+-implanted InGaAs by means of Raman scattering

“…10 The lowest frequency peak in the optical phonon region (200-300 cm Ϫ1 ) that is observed at 232 cm Ϫ1 is due to the InAs-like LO mode, whereas the peak that can be seen at Ϸ244 cm Ϫ1 has been identified as an intrinsic disorderactivated mode of the alloy. 11,12 Disorder-activated modes also give rise to Raman scattering bands in the acoustic phonon region (40-200 cm Ϫ1 ). The broad band detected between 100 and 190 cm Ϫ1 contains contributions from the disorder-activated longitudinal acoustic modes ͑DALA͒ as well as from the second-order transverse acoustic ͑2TA͒ modes of the In 0.53 Ga 0.47 As lattice, whereas the weaker band centered at Ϸ60 cm Ϫ1 is due to disorder-activated transverse acoustic ͑DATA͒ modes.…”

Spectroscopic investigation of strain induced by compositional variation in bulk InxGa1–xAs crystal grown by MCZM method

“…However, depending upon the crystal orientation and experimental geometry one of them may be optically forbidden [12]. The ternary compound semiconductor In x Ga 1-x As shows two-mode behavior [7,[13][14][15] in the first-order Raman scattering, in which LO and TO phonons corresponding to both InAs and GaAs binary end materials are found. The appearance and frequency position of these phonons depend on the compositional fraction, x [7,15].…”