Researchers at Pennsylvania State University have designed a III-V heterojunction tunnel field-effect transistor (HTFET)-based radio-frequency (RF) rectifier. Benchmarking of the HTFET-based differential-drive rectifier has shown promise compared to the state-of-the-art passive RF identifiers (RFIDs). With the 10-stage optimized TFET rectifier at 915 MHz, power conversion efficiency of 98% with 0.5-nW power consumption, sensitivity of -24 dBm for 9 μW DC power output (PDC), and sensitivity of -33 dBm for 0.4 μW PDC have been achieved.