Plenty of Room at the Bottom and Top: Future Perspectives on GaN Power Devices and Applications

GaN power devices have achieved commercial success primarily in the 30-900 V range, particularly in consumer electronics. Yet, to borrow from Richard Feynman's famous remark, there remains plenty of room at both the “bottom” and the “top”- not only in voltage classes, with opportunities at both lower and higher ends, but also in integration scale, spanning from fundamental device architectures to monolithic integration. This paper explores the untapped potential of GaN power technology across these domains, beginning with both ends of the voltage spectrum: low-voltage (<30-50 V) and high-voltage (>1 kV) applications. We highlight emerging GaN device structures under industrial development, analyze their performance limits, and examine transformative GaN applications enabled by these devices, including AI processor power delivery, humanoid robotics, light detection and ranging (LiDAR), electric vehicles (EVs), electric vertical take-off and landing (eVTOL) aircraft, MVDC power supplies, and solid-state circuit breakers. Beyond voltage scaling, we explore the promise of monolithic bidirectional GaN switches for various AC power conversion applications, and evaluate GaN's applicability in cryogenic and high-temperature environments for quantum and aerospace systems. Finally, we discuss packaging advances essential to supporting these device capabilities. This work provides a comprehensive perspective on extending the frontier of GaN power electronics and coordinating progress in devices and circuits for next-generation applications.