Optical and electrical characterization of Si/Ge superlattices

Abstract

Using recent studies of absorption and photoluminescence, different junction space charge techniques have been employed to separate intrinsic signals from extrinsic responses in ultrathin Si/Ge superlattices. The diodes showed good I–V characteristics with ideality factors of about 2 and a reverse current of about 10 −11 A for voltages less than 1 V. The extrinsic photoionization cross-section spectrum exhibited oscillatory properties which are discussed in terms of Wannier-Stark localization.