A large Rashba splitting enhanced by an in‐plane magnetic field is observed in non‐magnetic InGaAs/GaAsSb/InGaAs resonant tunneling diodes over a wide range of temperatures. The current resonances split by the Rashba effect reveal peak to valley ratios up to 2.5:1, the energy spacing between the split peaks reaches values up to 30 meV at
The observed peak splitting is robust and can be observed at temperatures as high as
The largest Rashba parameter determined from the split peak positions is
This value is consistent with literature values reported for InGaAs based devices.