InP Three Level Transferred Electron Devices

Evidence gathered from experiments with bulk InP shows that both domain and higher frequency, current controlled, instabilities can occur. Device results show typically broad tuning ranges centred on a frequency well above the domain frequency suggesting that the mode of operation of devices relates more to the higher frequency modes observed in bulk material. Theoretically, domain inhibition can result from a three level transfer mechanism, and accumulation modes seem naturally favoured. However, no direct confirmation of three level transfer yet exists. Devices have operated under pulsed conditions at frequencies up to 40 GHz; with efficiencies up to 8% at X band and 2% at Q band and CW operation has been obtained at Q band. These results suggest reasonable device prospects for InP.