Recent Advances in Silicon Photodetectors Based on the Internal Photoemission Effect

Abstract

Silicon technologies provide an excellent platform in order to realize microsystems where photonic and microelectronic functionalities are monolithically integrated on the same substrate. In recent years, a lot of passive and active silicon photonic devices have been optimized to work at telecom wavelengths where, unfortunately, silicon has a neglectable optical absorption due to its bandgap of 1.12 eV. Although silicon cannot detect wavelengths above 1.1 μm, in recent years, tremendous advances have been made in order to make it suitable for operation in the near-infrared spectrum. One of the approaches is to take advantage of the internal photoemission effect through a Schottky junction where a metal absorbs the incoming radiation and emits hot carriers into silicon making sub-bandgap detection possible. The present chapter describes the more recent advances in the field of the silicon photodetectors based on the internal photoemission effect showing as devices based on new emerging materials and complex nanostructure are leading this family of device to compare favorably with the well-established technologies commonly used for telecom wavelengths based on germanium and III-V semiconductors.

Integrated Photodetectors Based on Group IV and Colloidal Semiconductors: Current State of Affairs

“…Several new structures have been reported in literature combining, for example, IPA with nanoscale metallic structures, comprising Si nanoparticles (NPs) [ 39 ], metal stripes allowing surface plasmon polaritons (SPPs) [ 40 , 41 ], metallic gratings [ 42 ] and new structures based on two-dimensional materials (like graphene) capable to substitute metal in the Schottky junction [ 43 ]. Moreover, as reported in some complete review on this topic [ 44 , 45 ], due to the unipolar nature of the Schottky junction, IPE based PDs are very fast and can be monolithically integrated with Si-based CCD for IR applications [ 46 ].…”

Schottky Photodiodes in Bulk CMOS for High-Speed 1310/1550 nm Optical Receivers

“…Custom process silicon IPE based detectors have been demonstrated in literature, of which an overview is given in [28]. The results vary widely, with responsivities ranging from 10 μA/W to 1.25 A/W.…”