Semiconductor nanocrystals (NCs) offer new opportunities for optical and electronic devices ranging from single-electron transistors to large-area solar cells. Solution synthesis methods cannot reach the temperatures necessary to produce crystalline nanoparticles of covalently bonded materials, and most gas-phase techniques suffer from particle agglomeration and sintering. Nonthermal plasma synthesis, however, can produce high-quality NCs of key materials such as Si and Ge. In this review, we examine the current state and future challenges of the growing field of plasma-synthesized NCs from a device applications perspective. We identify NC microstructure, morphology, ensemble monodispersity, surface chemistry and doping as being vital to the success of next-generation devices, and we discuss research opportunities to understand and control these properties during plasma synthesis.