Interfacial properties of n-GaAs and polymer deposited by plasma chemical vapor deposition

The passivating effects of plasma polymerized thin films of thiophene on the intrinsic properties of the surface of n-GaAs (100) have been studied by means of Raman scattering, photoluminescence, and capacitance-voltage measurements. After passivation, the low-temperature photoluminescence efficiency of n-GaAs is increased three times and the surface barrier at the interface between polymer and GaAs is reduced. The surface electric field and barrier height determined by Raman scattering studies and also from capacitance-voltage measurements are shown to be lowered implying that the band bending is controlled externally.