ENHANCED OPTICAL-ABSORPTION IN MICROCRYSTALLINE SILICON

An enhanced optical absorption, compared to crystalline silicon, was o bserved in the above gap region together with very low defect-connecte d absorption in microcrystalline silicon (mu c-Si:H) prepared by very high frequency glow discharge technique at 70 MHz. As the mu c-Si:H ma terial has a very low fraction of amorphous phase, a 'crystalline sili con like' absorption model is proposed which associates most absorptio n properties of mu c-Si:H to the crystalline phase in the material. Th ereby the influence of internal strain, microcrystallite boundaries, h ydrogen content and elastic light scattering on the absorption propert ies are discussed.