GaAs Raman scattering

Fig. 2.3. The Fourier-transformed (FT) intensity of coherent phonons as a function of the pump polarization angle ip for a GaAs/Alo.36Gao.64As MQW. The excitation wavelength is slightly above the n = 1 exciton resonance (left) and slightly above the n = 2 subband energy (right), ( -dependent component is attributed to ISRS, while the ( -independent component is to TDFS and forbidden Raman scattering. From [20]...

Fig. 8. Frequency shift of the Raman-scattered light in GaAs at room temperature as a function of the square root of the electron concentration 4 )...

In thick ( 300 pm) crystals of GaN electronic excitons of shallow dopants have been observed in far infrared absorption at 215 cm 1 [44], Interpreted as the ls-2p transition of a residual shallow donor, its binding energy was calculated to be (35.5 0.5) meV. Further modes at 149 and 242 cm 1 have been observed in mixed phase GaN/GaAs in Raman scattering and have been associated with electronic excitations of shallow donors in cubic and sphalerite GaN, respectively [45] see also [46], Far infared absorption at 23.2 cm 1 in magnetic fields has been used to determine the effective electron mass in GaN, m = 0.20 0.005 m, (corrected for polaron effects) in cyclotron resonance [47]. 

Figure 4.8-20 Raman scattering of GaAs with free carriers, n = 1.75 lO cm and two different scattering geometries, according to Mooradian 1972, (a) and phonon-plasmon interaction vs. square root of carrier concentration, according to Mooradian and McWorther, 1967, (b).

An interesting possibility is inducing SERS activity, in a non-SERS-active substrate, by depositing submonolayer quantities of silver on its surface. Van Duyne and Haushalter used this method to measure Raman scattering from a GaAs semiconductor interface. There was also an experiment to use a silver underlayer to induce SERS in a layer covering it. ... 

Prettl et al (1973) studied the far infrared spectra of a-Ge, GaP, GaAs and InAs and compared them with the Raman spectra. They showed that the spectra are similar in the optical phonon frequency regions but the absorption is much smaller at low frequencies. They argue that this effect is due to the different dependence of the coupling constant for Raman scattering and infrared absorption on the wavevector q. 

Table 4.1-43 Phonon wavenumbers of aluminium compounds aluminium nitride (300 K, from Raman scattering) aluminium Phosphide (from Raman spectroscopy) aluminium arsenide (from Raman spectroscopy 0.5 p.m layer of AlAs on GaAs T = 31K) aluminium antimonide (from Raman spectroscopy)...

For GaAs values for the EP scattering matrix element from r-X and r-L have been deduced by various experiments such as transferred electron effects and time-dependent Raman scattering. In general, these workers find that 2... 

AK Sood, J Menendez, M Cardona, K Ploog. Resonance Raman-scattering by confined LO and TO phonons in GaAs-AlAs superlattices—response. Phys Rev Lett 56 1753, 1986. 

J Menendez, M Cardona. Interference effects—A key to understanding forbidden Raman-scattering by LO phonons in GaAs. Phys Rev B 31 3696-3704, 1985. 

W Bala, M Drozdowski, M Kozielski. Study of misfit dislocations profiles in ZnSe/GaAs structures by Raman scattering. Acta Phys Polonica A84 689-692, 1993. 

S Nakashima, A Fujii, K Mizoguchi, A Mitsuishi, K Yoneda. Raman-scattering measurements of strains in ZnSe epitaxial-films on GaAs. Jpn J Appl Phys 27 1327-1330, 1988. 

RC Miller, DA Kleinman, AC Gossard. Observation of doubly resonant LO-phonon Raman-scattering with GaAs-ALGai j,As quantum wells. Solid State Commun 60 213—216, 1986. 

F Cerdeira, E Anastassakis, W Kauschke, M Cardona. Stress-induced doubly resonant Raman-scattering in GaAs. Phys Rev Lett 57 3209-3212, 1986. 

T Ruf, C Trallero-Giner, RT Phillips, M Cardona. Resonant magneto-Raman scattering in GaAs. Phys Rev B 41 3039-3047, 1990. 

Table 4.1-59 Phonon wavenumbers of gallium compounds. Gallium nitride (GaN), T = 300K, from Raman spectroscopy gallium phosphide (GaP), RT, from an analysis of Raman, neutron, luminescence, and absorption data gallium arsenide (GaAs), T = 296 K, from coherent inelastic neutron scattering gallium antimonide (GaSb), T = 300 K, from second-order Raman effect...

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