Nanocrystals for silicon-based light-emitting and memory devices

Abstract

Nanocrystals (NCs), representing a zero-dimensional system, are an ideal platform for exploring quantum phenomena on the nanoscale, and are expected to play a major role in future electronic and photonic devices. Here we review recent progress in the growth, characterization and utilization of some group-IV semiconductors (Si and Ge), metal and high-k NCs for silicon planar technology compatible light-emitting and floating gate memory devices. We first introduce the size-dependent electrical and optical properties of Si and Ge NCs. We outline some of the schemes to achieve light emission from indirect band gap Si and Ge NCs embedded in different high band gap oxide matrices. In particular, special emphasis is given on the review of the advances in Ge NCs because of some of their intriguing electronic and optical properties. We then describe the use of semiconductor and metal NCs as floating gates for non-volatile memory devices to achieve high data retention and faster program/erase speeds. The exploitation of high-k oxides with tunable and variable injection barriers for improved charge storage devices is discussed. Finally, the integration of single and multilayer metallic NCs and multilayer high-k oxides as floating gates is explored by the fabrication and testing of memory transistors.