The semiconductor industry has long been built around silicon-based CMOS transistors. However, as artificial intelligence demands ever greater computing power, conventional silicon technologies are approaching their limits in delivering high-performance, low-power computation. Simply continuing to shrink transistor dimensions is no longer sufficient to overcome these fundamental constraints. As the era of silicon scaling draws to a close, it is time to explore a paradigm shift toward entirely new device concepts. What are the most promising alternatives to silicon-based devices, and what scientific and technological challenges must be overcome to bring them into practical semiconductor platforms?