We show the experimental realisation of fundamental mode operation of planar Gunn diode structures fabricated in GaAs/AlGaAs quantum wells. The electron density in the active channel is enhanced by positioning double delta-doping layers on either side. Small signal measurement shows that a typical device exhibits negative resistance up to 158 GHz. Using this device structure we have demonstrated a planar Gunn oscillator working at 115.5 GHz with an output power of -28 dBm.
Li, C., Khalid, A., Pilgrim, N., Holland, M. C., Dunn, G., & Cumming, D. R. S. (2009). Novel planar Gunn diode operating in fundamental mode up to 158 GHz. Journal of Physics: Conference Series, 193(1), . https://doi.org/10.1088/1742-6596/193/1/012029