That's the BEST one YET an Esaki or Tunnel Diode from a transistor??? I DON'T THINK SO. the construction of a tunnel diode isn't even in the same league as a common bi-polar. A Zener diode yes, the emitter/base junction... somewhat noisy and not a real sharp zener knee but a 6 to 7.5 V zener can be made from a bipolar and an SCR can easily be made from a complimentary pair... an NPN and a PNP make a regenerative switch that works like an SCR and will switch in all 4 quadrants. Some make common base oscillators that can go quite high in frequency. But not a back or tunnel diode. I've never that I remember seen a bipolar device display negative resistance, or at least useful negative resistance...
Bob