Tunable Acoustoelectric Devices Using a P–N Junction for RF Signal Processing and RF to DC Conversion

Abstract

This UCF invention introduces a new type of device that turns radio-frequency (RF) signals into usable electrical power without relying on traditional diodes or complex circuits. Instead of physically thinning semiconductor materials—which usually damages them—this device uses the natural electric field inside a p–n junction to create a clean, extremely thin region where signals can be converted more efficiently. When acoustic waves move through the device, they push charge carriers in this controlled region and generate a strong DC output. Because the device’s behavior can be tuned during fabrication or adjusted electronically during operation, it can be optimized for many uses, including low-power sensors, remote powering, and RF-based wake-up systems.

Technical Details: The device is built as a suspended membrane that includes a piezoelectric layer and a semiconductor stack forming a p–n junction. Interdigital transducers launch Lamb waves through the membrane, producing an electric field that interacts strongly with carriers confined in a depletion-defined channel. Unlike physical thinning, this “electrical thinning” preserves crystal quality and mobility, strengthening the acoustoelectric response.

Measurements show that the full heterostructure generates significantly higher voltage and current compared to devices where the p-type layer is removed or the semiconductor is physically thinned. The platform also supports tunability: changing the junction doping or applying a small external bias modifies the depletion width, allowing the device to shift between high-sensitivity and high-current modes depending on the application.

Benefit

Market Application