Plasmonic nanoparticle scattering for enhanced performance of photovoltaic and photodetector devices

A variety of approaches are examined for exploiting the optical properties of metal or dielectric nanoparticles, particularly those associated with surface plasmon polariton resonances, to improve the performance of semiconductor photodetectors and photovoltaic devices. Early and recent concepts for employing optical absorption and local electromagnetic field amplitude increases associated with surface plasmon polariton excitation to improve photocurrent generation in organic photovoltaic devices are briefly reviewed. The application of optical scattering properties of nanoparticles to improve transmission of optical power into, and consequently photocurrent response in, Si and a-Si:H photodiodes is then described, and effects related to scattered-wave phase shifts and interference effects between scattered and directly transmitted wave components in producing either enhancement or suppression of photocurrent response at different wavelengths are discussed. Coupling of photons incident normal to the surface of a semiconductor thin-film device into lateral, optically confined paths within waveguide structures formed by refractive index contrast either within the semiconductor structure, or between the semiconductor and surrounding dielectric material, is discussed in the context of early and recent studies of such coupling in silicon-on-insulator photodetectors, and recent work on engineering of photon propagation paths in III-V compound semiconductor quantum well solar cells.