GaAs carrier wave growth in the presence of a thin resistive surface layer

Thin sheets of resistive material deposited on epitaxial GaAs in order to provide uniform electric field profiles are predicted to still allow microwave gain while suppressing instabilities at all lower frequencies. The gain threshold frequency depends upon the device thickness, the surface resistance of the resistive layer, etc. The mode exhibits a higher cutoff frequency beyond which the gain is not possible because of the severe diffusion losses. Broad-band gain is predicted in the 10-20 GHz range.