Piezoelectric semiconductor acoustic cavities

Abstract

We describe semiconductor cavities based on strained Ga0.85In0.15As/AlAs multilayers with permanent built-in piezoelectric fields that confine acoustic phonons in the THz range. The possible role of piezoelectric fields on the phonon lifetimes and on Raman scattering is discussed. Phonon mirrors and cavities grown along [001] (non-piezoelectric) and along [311] (piezoelectric) are studied and compared using high-resolution Raman spectra and photoelastic model calculations. The high quality of the grown [001]([311]) structures is demonstrated by the observation of up to 7(5) orders of folded acoustic phonons and the excellent agreement with theory. We observe a large broadening of the acoustic phonon peaks in the piezoelectric [311] structures upon carrier injection with near-gap excitation. Such acoustic phonon lifetime reduction evidences a strongly modified electron-acoustic phonon interaction in these structures

Acoustic phonon Raman scattering induced by a built-in electric field

“…8 These results suggest that the modulation of the built-in fields by the acoustic phonon strain should open an additional channel of electron-acoustic-phonon coupling that could, in principle, be tailored and dynamically controlled. 10 In this paper, we report the first observation of electric-field induced Raman scattering by acoustic phonons in strained ͓311͔ Ga 0.85 In 0.15 As/ AlAs superlattices with permanent built-in piezoelectric fields. We demonstrate that the Raman process is strongly resonant with a forbidden interband transition involving the second confined heavy-hole ͑hh 2 ͒ and the first confined electron ͑e 1 ͒ levels.…”

“…It has been recently pointed out that a different situation may arise when built-in permanent piezoelectric fields are present. [6][7][8][9][10] Interestingly, a huge acoustic phonon coherent generation efficiency has been reported in GaInN/GaN piezoelectric superlattices ͑SLs͒, which is more than 2 orders of magnitude larger than that observed in standard GaAs/AlAs structures. 6,7 The proposed mechanism involves the screening of the piezoelectric built-in field by photoexcited carriers, which triggers an instantaneous coherent displacement with wave vector determined by the SL period.…”

Analysis of a Circular Piezoelectric Semiconductor Embedded in a Piezoelectric Semiconductor Substrate

“…Relevant material parameters for a few common piezoelectric semiconductors of 6 mm symmetry are [1,[19][20][21][22][23][24] ε 11 /ε 0 e 15 …”

“…In a way similar to Eqs. (13)- (15), taking into consideration that K 1 (ξ ) is unbounded at the origin, we can write the interior solution as n = C 4 I 1 β r cos θ,…”

“…In these composites, the component phases do not have to be piezoelectric semiconductors because the acoustoelectric effect can be produced in composites of piezoelectric dielectrics and nonpiezoelectric semiconductors [5], in which the acoustoelectric effect is due to the combination of the piezoelectric effect and the semiconduction in each component phase. Piezoelectric semiconductors have been under sustained study for various device applications [11][12][13][14][15][16]. In this paper, we analyze a circular inclusion of a piezoelectric semiconductor embedded in a matrix of a different piezoelectric semiconductor.…”