Jayaraman, A. ; Kourouklis, G. A. ; People, R. ; Sputz, S. K. ; Pfeiffer, L. (1990) Pressure-tuned resonance Raman scattering and photoluminescence studies on MBE grown bulk GaAs at the E0 gap Pramana - Journal of Physics, 35 (2). pp. 167-176. ISSN 0304-4289
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Official URL: http://www.ias.ac.in/j_archive/pramana/35/2/167-17...
Related URL: http://dx.doi.org/10.1007/BF02875290
Abstract
Hydrostatic pressure has been used to tune in resonance Raman scattering (RRS) in bulk GaAs. Using a diamond anvil cell, both the photoluminescence peak (PL) and the 2 LO and LO-phonon Raman scattered intensities have been monitored, to establish RRS conditions. When the E0 gap of GaAs matchesħω S orħω L, the 2 LO and LO-phonon intensity, respectively, exhibit resonance Raman scattering maxima, at pressures determined byħω L. With 647.1 nm radiation (ħω L = 1.916 eV), a sharp and narrow resonance peak at 3.75 GPa is observed for the 2 LO-phonon. At this pressure the 2 LO-phonon goes through its maximum intensity, and falls right on top of the PL peak, revealing thatħω S(2 LO) =E 0. This is the condition for “outgoing” resonance. Experiments with other excitation energies (ħω L) show, that the 2 LO resonance peak-pressure moves to higher pressure with increasingħω L, and the shift follows precisely theE 0 gap. Thus, the 2 LO RRS is an excellent probe to follow theE 0 gap, far beyond the Γ-X cross-over point. A brief discussion of the theoretical expression for resonance Raman cross section is given, and from this the possibility of a double resonance condition for the observed 2 LO resonance is suggested. The LO-phonon resonance occurs at a pressure whenħω L ≈E 0, but the pressure-induced transparency of the GaAs masks the true resonance profile.
Item Type: | Article |
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Source: | Copyright of this article belongs to Indian Academy of Sciences. |
Keywords: | Pressure-Tuning; Resonance Raman Scattering; Semiconductors; 62.50; 78.30; 78.55 |
ID Code: | 96091 |
Deposited On: | 04 Dec 2012 09:30 |
Last Modified: | 19 May 2016 08:37 |
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