Low shot noise in high-speed resonant-tunneling diodes

Experimental and theoretical results are presented on microwave shot noise in high-speed double-barrier resonant tunneling diodes (RTDs). It is found that the room-temperature shot noise per unit current can be more than a factor of two lower than in single-barrier structures (e.g. p-n junctions) when the RTD is biased into the positive differential resistance (PDR) region below the current peak, but that it is increased when biased into the negative differential resistance (NDR) region. The analysis suggests that the reduced shot noise could also be obtained in other double-barrier resonant-tunneling devices that operate in the PDR region, such as resonant-tunneling transistors and the quantum-well injection and transit time oscillator.