Synthesis and Luminescent Properties of Silicon Nanocrystals

Antonio Coyopol-Solis,Alfredo Morales-Sánchez,Godofredo García-Salgado,Tomás Díaz-Becerril,Liliana Palacios-Huerta,Santiago A Cabañas-Tay

doi:10.5772/intechopen.74286

Abstract

Nowadays, study of silicon-based visible light-emitting devices has increased due to large-scale microelectronic integration. Since then different physical and chemical processes have been performed to convert bulk silicon (Si) into a light-emitting material. From discovery of Photoluminescence (PL) in porous Silicon by Canham, a new field of research was opened in optical properties of the Si nanocrystals (Si-NCs) embedded in a dielectric matrix, such as SRO (silicon-rich oxide) and SRN (silicon-rich nitride). In this respect, SRO films obtained by sputtering technique have proved to be an option for light-emitting capacitors (LECs). For the synthesis of SRO films, growth parameters should be considered; Si-excess, growth temperature and annealing temperature. Such parameters affect generation of radiative defects, distribution of Si-NCs and luminescent properties. In this chapter, we report synthesis, structural and luminescent properties of SRO monolayers and SRO/SiO2 multilayers (MLs) obtained by sputtering technique modifying Si-excess, thickness and thermal treatments.

Highlights

The use of photonic signals instead of electrons to transmit information through an electronic circuit is an actual challenge
Results about of Si nanocrystals (Si-NCs) embedded at silicon-rich oxide (SRO) monolayer and SRO/SiO2 MLs deposited by the RF Co-sputtering method as a function of Si-excess (5.2–14.3 at.%) and modulating the SRO-thickness layer (2.5–7.5 nm) of MLs are shown
Most intense photoluminescence is achieved using SRO layers with 5 nm thick and 14 at.% of Si-excess. Such effect is important for the design of electroluminescent devices, for supplying low voltages, since a large number of Si-NCs are generated as Si-excess increases

Summary

Introduction

The use of photonic signals instead of electrons to transmit information through an electronic circuit is an actual challenge. Results about of Si-NCs embedded at SRO monolayer and SRO/SiO2 MLs deposited by the RF Co-sputtering method as a function of Si-excess (5.2–14.3 at.%) and modulating the SRO-thickness layer (2.5–7.5 nm) of MLs are shown. SRO monolayers and SRO/SiO2 MLs have a broad emission band in the orange-red region (1.45–2.3 eV). The SRO/SiO2 MLs emit a stronger PL intensity compared with SRO monolayers. The most intense PL emission is observed in MLs when the SRO-thickness is 5 nm, and with the highest Si-excess (14.3 at.%), which is important for the design of electroluminescent devices with low threshold voltage. A comprehensive study of synthesis of Si-NCs in SRO and SRO/SiO2 MLs as a function of Si-excess (5.2–14.3 at.%) and annealing temperature is presented

Experimental procedure

Deposition rate Si and SiO2 films

SRO monolayers

SRO monolayer The nature of the chemical bonds and the phase separation of

SRO Monolayers

SRO/SiO2 MLs

Conclusion