Nanocrystalline Ceramics

Chapter 2

Abstract

memristor

9

1. Introduction

Silicon Nanocrystals and

Vladimir Volodin, Vladimir Gritsenko,

Andrei Gismatulin and Albert Chin

effects in SiOx films are discussed.

Amorphous Nanoclusters in SiOx

Structure, and Memristor Effects

Semiconductor nanocrystals in dielectric films are interesting from fundamental aspect, because quantum-size effects in them appear even at room temperature, so such objects can be called as "quantum dots". Silicon nanocrystals and amorphous silicon nanoclusters in substoichiometric SiOx and SiNx films are traps for electrons and holes that apply in nonvolatile memory devices. In this chapter the formation of silicon nanocrystals and silicon amorphous nanoclusters in SiOx and SiNx films was studied using structural and optical methods. The phonon confinement model was refined to obtain sizes of silicon nanocrystals from analysis of Raman scattering data. Structural models that lead to nanoscale potential fluctuation in amorphous SiOx and SiNx are considered. A new structural model which is intermediate between random mixture and random bonding models is proposed. Memristor

Keywords: silicon suboxides, silicon subnitrides, nanocrystals, amorphous nanoclusters, phonon confinement model, nanoscale potential fluctuations,

systems are manifested even at room temperature. For example, a bright

Nanometer-sized semiconductor crystals, the so-called nanocrystals (NCs) and amorphous nanoclusters, embedded in wide-gap insulating matrices, have shown significant promises for application in nanoelectronics (nonvolatile memory) and optoelectronics (light-emitting diodes (LEDs)) [1]. Quantum effects in such hetero-

photoluminescence (PL) was observed in dodecyl-passivated colloidal Si NCs with external quantum efficiency (QE) up to 60% [2]. Since in some experiments single NCs originated delta-function-like energy photoluminescence spectra [3], they can be called as quantum dots. In metal-dielectric-semiconductor structures based on SiNx films with Si nanoclusters, an effective electroluminescence with red, green, and blue light-emitting diodes was demonstrated [4]. Since NCs in a dielectric matrices act also as traps for charge carriers, the NCs' based structures have also

and SiNx: Atomic, Electronic

### Chapter 2
