Comparison of resonant tunneling in a double-quantum-well three-barrier system and a single-quantum-well double-barrier system

A theoretical analysis has been carried out to compare the tunneling processes in a double-quantum-well three-barrier (DQW-TB) system and a single-quantum-well double-barrier (SQW-DB) system. Based on a general WKB formula, it is shown that a symmetric DQW-TB system with transparency-matched barriers is far superior to the SQW-DB system in a number of aspects, including the peak current, the peak-to-valley ratio, and the speed limit.