Decoupling the effects of confinement and passivation on semiconductor quantum dots.

Roya Rudd,Peter J Murphy,Drew Evans,Peter J Reece,Eric Charrault,Colin Hall

doi:10.1039/c6cp03438a

Abstract

Semiconductor (SC) quantum dots (QDs) have recently been fabricated by both chemical and plasma techniques for specific absorption and emission of light. Their optical properties are governed by the size of the QD and the chemistry of any passivation at their surface. Here, we decouple the effects of confinement and passivation by utilising DC magnetron sputtering to fabricate SC QDs in a perfluorinated polyether oil. Very high band gaps are observed for fluorinated QDs with increasing levels of quantum confinement (from 4.2 to 4.6 eV for Si, and 2.5 to 3 eV for Ge), with a shift down to 3.4 eV for Si when oxygen is introduced to the passivation layer. In contrast, the fluorinated Si QDs display a constant UV photoluminescence (3.8 eV) irrespective of size. This ability to tune the size and passivation independently opens a new opportunity to extending the use of simple semiconductor QDs.

Highlights

With the breakthroughs over the past decades in Semiconductor (SC) materials and processing, SCs have been critical to rapid development of today’s modern electronic and optoelectronic devices
The role of Perfluorinated Polyether (PFPE) in this study is as the capture medium for collecting and stabilizing SC quantum dots (QDs), PFPE which contains many F atoms was selected as the dielectric matrix
We show that using the PFPE as the matrix improves the optical properties of resultant SC QDs

Summary

Introduction

With the breakthroughs over the past decades in Semiconductor (SC) materials and processing, SCs have been critical to rapid development of today’s modern electronic and optoelectronic devices.

Results

Conclusion