Abstract
Progress in multiple-valued logic (MVL) depends much on the development of devices that are inherently suitable for MVL operation. With their multiple stable states, resonant tunneling devices are promising candidates. Although not at a matured stage yet, resonant tunneling transistors (RTTs) and diodes (RTDs) are expected to be indispensable for practical applications of MVL in the near future. In this paper, state-of-the-art RTT technology is reviewed with some issues to be addressed. Possible applications are also discussed in terms of coupled-quantum-well base RTTs and monostable-multistable logic circuits.