Gallium nitride (GaN) is a wide-bandgap semiconductor with high electric field strength and electron mobility, making it promising for high-frequency communications and photonic applications. Recent advances in GaN growth on large-area substrates have brought power conversion applications to the verge of commercialization. The 2018 GaN power electronics roadmap outlines current and future challenges in GaN technology, including manufacturing challenges, epitaxial lift-off, buffer design, and growth techniques. GaN-on-Si power devices are being developed for high-performance, cost-effective applications, with a focus on improving device reliability, reducing on-resistance, and enhancing thermal performance. The roadmap highlights the importance of GaN in emerging markets such as electric vehicles, renewable energy, and high-speed computing. Challenges include achieving high breakdown voltages, reducing device size, and improving integration with other electronics. Advances in epitaxial lift-off, buffer design, and growth techniques are critical for overcoming these challenges and enabling the widespread adoption of GaN in power electronics. The roadmap also emphasizes the need for further research and development to optimize GaN-based power devices for a wide range of applications.Gallium nitride (GaN) is a wide-bandgap semiconductor with high electric field strength and electron mobility, making it promising for high-frequency communications and photonic applications. Recent advances in GaN growth on large-area substrates have brought power conversion applications to the verge of commercialization. The 2018 GaN power electronics roadmap outlines current and future challenges in GaN technology, including manufacturing challenges, epitaxial lift-off, buffer design, and growth techniques. GaN-on-Si power devices are being developed for high-performance, cost-effective applications, with a focus on improving device reliability, reducing on-resistance, and enhancing thermal performance. The roadmap highlights the importance of GaN in emerging markets such as electric vehicles, renewable energy, and high-speed computing. Challenges include achieving high breakdown voltages, reducing device size, and improving integration with other electronics. Advances in epitaxial lift-off, buffer design, and growth techniques are critical for overcoming these challenges and enabling the widespread adoption of GaN in power electronics. The roadmap also emphasizes the need for further research and development to optimize GaN-based power devices for a wide range of applications.