Towards single-chip radiofrequency signal processing via acoustoelectric electron-phonon interactions

Area of Science:

• Materials Science
• Electrical Engineering
• Acoustics

Background:

• Passive piezoelectric acoustic wave technologies lack active functionalities.
• Achieving all-acoustic radiofrequency (RF) signal processors requires integrating nonlinear and nonreciprocal components.

Purpose of the Study:

• To develop a heterogeneously integrated acoustoelectric material platform for all-acoustic RF signal processing.
• To demonstrate key components of an all-acoustic RF signal processor.

Main Methods:

• Fabrication of a 50 nm indium gallium arsenide (InGaAs) epitaxial semiconductor film on a 41° YX lithium niobate (LiNbO3) piezoelectric substrate.
• Demonstration of passive delay line filters, amplifiers, and circulators using the integrated platform.

Main Results:

• Achieved highest performing surface acoustic wave (SAW) amplifiers in terms of gain per unit length and DC power dissipation.
• Demonstrated the first acoustoelectric circulator with 46 dB isolation using pulsed DC bias.
• Heterogeneous integration enabled independent optimization of piezoelectric-acoustic and electronic properties.

Conclusions:

• The developed acoustoelectric material platform is a significant step towards ultra-compact, all-acoustic RF signal processors.
• This work provides a foundation for realizing the remaining components of such processors.
• The demonstrated components show superior performance, highlighting the potential of this integrated approach.