Fundamental oscillation up to 1.08 THz in resonant tunneling diodes with high indium composition transit layers

Fundamental oscillations up to 1.08 THz with the output power of 5.5 μW was achieved at room temperature in GaInAs/AlAs resonant tunneling diodes (RTDs) with thin barriers, graded emitter, and high indium composition transit layers. A possible increase in collector transit time due to the G-ΓL transition has been discussed in the RTDs oscillating at 1.04 THz reported recently, in which the graded emitter was introduced to suppress this transition with a reduced electric field. In this paper, high indium composition transit layers were adopted in addition to the graded emitter for further reduction in collector transit time with large G-ΓL separation as well as with the increment of the launching velocity. From the comparison between the measured and theoretical results, the collector transit time was estimated to be slightly reduced by the addition of this structure.