Plasmon enhanced resonant defect absorption in thin a-Si:H n-i-p devices

By embedding silver nanoparticles (Ag NPs) of approximately 20 nm diameter inside the intrinsic layer of thin hydrogenated amorphous silicon (a-Si:H) n-i-p devices, a photocurrent is measured for photon energies below the a-Si:H bandgap. This is attributed to the excitation of charge carriers from defect states created by the incorporation of the Ag inside the silicon network. The defect location inside the strong electromagnetic fields close to the resonant absorbing NPs enables high transition rates. This is a proof of concept for the use of the impurity photovoltaic effect in a-Si:H devices.