Wireless acoustic-driven current source achieving nanoampere-level at millimeter-scale

Piezoelectric surface acoustic wave devices can drive charge carriers in semiconductors through the acoustoelectric effect, generating direct currents with potential applications in sensing and biomedicine. However, current sources based on this mechanism that combine nanoampere-level precision, a wide dynamic range, and long-term operational stability have yet to be demonstrated. Here, we demonstrate an acoustically driven current source based on an InSb heterostructure integrated with a piezoelectric substrate. The output current is tunable from 1.22 nA to 25.46 μA by adjusting the input radio-frequency power, with a sensitivity down to the nanoampere scale. At an input power of 10 mW, the device delivers an average output current of 1.54 μA with 1% accuracy and maintains a standard deviation of 4.82 nA over 12 h of continuous operation. Its acoustic-to-electrical conversion efficiency can be further enhanced by implementing multiple interdigital transducer arrays and single-phase unidirectional transducer structures, enabling cooperative excitation and directional acoustic energy propagation. The device also supports wireless excitation and accelerates wound healing in a rat full-thickness skin defect model under low-intensity electrical stimulation. These results establish a wireless acoustoelectric platform for stable, tunable, and miniaturized current delivery, suggesting potential for biomedical applications.