Realization of temperature-compensated GaAs surface acoustic wave delay lines

Grudkowski, T.W.; Gilden, M.

doi:10.1063/1.92398

Cited by 19 publications

(3 citation statements)

References 5 publications

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“…The TCDs of the other transversal filters were estimated using the same method. We also characterized (001) GaAs-based SAW filters with the [1-10] propagation direction and confirmed that their TCD, 52.8 ppm/deg, is in good agreement with a previously reported value 5) (not depicted). The dependence of TCDs on hk, where h and k are the GaN layer thickness and SAW wave number (k ¼ 2=), respectively, for both propagation directions is shown in Fig.…”

supporting

confidence: 90%

Temperature Dependence of Surface Acoustic Wave Characteristics of GaN Layers on Sapphire Substrates

Nishimura¹,

Shigekawa²,

Yokoyama³

et al. 2005

Jpn. J. Appl. Phys.

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We measured surface acoustic wave (SAW) characteristics along the [01-10] and [2-1-10] directions of 1.5- and 2-µm-thick GaN layers on (0001) sapphire substrates at ambient temperatures between -50 and 200°C. The extracted thermal coefficient of delay (TCD) for the SAW propagating along the [01-10] direction, which is smaller than that for the SAW propagating along the [2-1-10] direction, decreases when GaN layer thickness, h, multiplied by SAW wave number, k, increases. The TCD for h k = 3.9, which might be close to that in bulk GaN, is as small as 28.3 ppm/deg. These results indicate that GaN is promising for SAW device operation over a wide range of ambient temperatures.

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supporting

confidence: 90%

Temperature Dependence of Surface Acoustic Wave Characteristics of GaN Layers on Sapphire Substrates

Nishimura¹,

Shigekawa²,

Yokoyama³

et al. 2005

Jpn. J. Appl. Phys.

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“…In this simple model, a relaxation time [25,26,28] of the 2D electron system is contained within the sheet conductivity such that…”

Section: Surface Acoustic Wave Technique As a Probe Of Crxx(co Q)mentioning

confidence: 99%

Experimental evidence for composite fermions

Willett

1997

Advances in Physics

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The study of correlated two-dimensional (2D) electron systems in the extreme quantum limit has been advanced by development of a field-theoretic model and associated experimental findings. The fundamental theoretical construction transforms the interacting 2D electrons into quasiparticles referred to as composite fermions. The properties of such an interacting particle system have recently been described, with the principal hypothesis that Fermi surfaces should form from the quasiparticle seas at specific ratios of the electron density to applied magnetic field. This model serves to provide an explanation for an extensive body of experimental data, including a description of the fractional quantum Hall effect as the integer quantum Hall effect for the quasiparticles. This review will present the experimental findings which both motivated and subsequently have verified aspects of this model. Following a brief introduction to 2D systems, early experimental findings pre-dating and influencing the composite fermion theory are examined. The theoretical construction and in particular the hypothesis of Fermi surface formation at high magnetic fields are briefly reviewed with respect to their experimental predictions. Experiments subsequent to the main theoretical developments are then presented. Emphasized are surface acoustic wave experiments which were responsible for measuring the composite fermion Fermi wave-vector and mean free path. Further demonstrations of semiclassical motion of the quasiparticles at the Fermi surface are also reviewed, including antidot experiments, magnetic focusing measurements, and transport studies through nar/ostructures. Experimental determination of the composite fermion effective mass is examined, considering results from measurements in dc transport, surface acoustic waves and thermopower. Extension of the theory and experi-ments to multiple filling factors in the magnetic field spectrum is also reviewed. Experimental findings are summarized and potential future studies are finally discussed. ContentsPAGE 1. Introduction 448 2. Background 450 2.1. Two-dimensional electron systems and the integer quantum Hall effect 450 2.2. Electron correlations and the fractional quantum Hall effect; Laughlin's wavefunction 451 2.3. Hierarchy of fractional quantum Hall states and the nonquantized Hall effect 454 2.4. Early surface acoustic wave results at a filling factor of 1/2 457 2.4.1. Surface acoustic wave technique as a probe of Crxx (co, q) 458 2.4.2. Surface acoustic wave technique at u= 1/2; enhanced conductivity at small length scales 464

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“…The TCF of SAW fabricated on AlN/GaN/sapphire with 2-mm-thick AlN was found to be À40:9 ppm/ C, whose absolute value is smaller than those of SAW fabricated on bulk LiNbO 3 and GaAs substrates. 12,[31][32][33] The reports about TCFs of SAW devices on AlN still vary for various cases. [34][35][36][37][38] It is known that there is a trade-off between piezoelectric coupling and TCF.…”

Section: Temperature Effect On Saw Characteristicsmentioning

confidence: 99%

Epitaxial AlN Thin Film Surface Acoustic Wave Devices Prepared on GaN/Sapphire Using Low-Temperature Helicon Sputtering System

Kao

Chen

Chien

et al. 2008

jjap

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High-quality epitaxial AlN films have been deposited on GaN/sapphire using helicon sputtering at a temperature of 300 C. The surface acoustic wave (SAW) characteristics, in terms of insertion loss, stopband rejection, and electromechanical coupling coefficient, of SAW devices fabricated on AlN/GaN/sapphire are much superior than those fabricated on GaN/ sapphire. The investigation of environmental effects, including temperature and relative humidity, shows that the ambient stability can be improved with the deposition of an AlN film on GaN/sapphire. An oscillator fabricated using an AlN/GaN/ sapphire-based SAW device was developed for application in sensors. The composite structure of AlN on GaN may bring about the development of high-frequency components, which integrate and utilize their semiconducting, optoelectronic, and piezoelectric properties.

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Realization of temperature-compensated GaAs surface acoustic wave delay lines

Cited by 19 publications

References 5 publications

Temperature Dependence of Surface Acoustic Wave Characteristics of GaN Layers on Sapphire Substrates

Temperature Dependence of Surface Acoustic Wave Characteristics of GaN Layers on Sapphire Substrates

Experimental evidence for composite fermions

Epitaxial AlN Thin Film Surface Acoustic Wave Devices Prepared on GaN/Sapphire Using Low-Temperature Helicon Sputtering System

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