Observation of multiple negative differential resistance in InP-InGaAs superlattice-emitter resonant tunneling bipolar transistor

Sequential resonant tunneling behavior of resonant tunneling bipolar transistor with 5-period i-InP/n-InGaAs superlattice emitter has been demonstrated. An interesting multiple negative-differential-resistance (NDR) phenomena resulting from the creation and extension of high-field domain in superlattice is observed at room temperature. Furthermore, the employing of a thin n-InGaAs emitter layer between InP/InGaAs superlattice and p⁺-InGaAs base layer helps to lower the potential spike at base-emitter junction and reduce neutral-emitter recombination current. Experimentally, the transistor performance, incorporating multiple NDR, with a relatively large current gain of 454 and an offset voltage as low as 80 mV is achieved.