Effects of the thickness on the properties of erbium‐doped silicon‐rich silicon oxide thin films

Abstract

The present study examines the influence of the layer thickness on the emission of Er ions coupled to Si nanoclusters within a silica matrix obtained by magnetron co‐sputtering at two typical temperatures (ambient and 500 °C. Such an investigation is essential to optimise the material for specific applications, inasmuch as thin layers of tens of nm are requested for electrically‐excited devices, while much thicker films (≥ 1 µm) are necessary for optically‐excited waveguides, lasers, etc. The Er PL was detected from as‐deposited samples with significant intensity for that grown at 500 °C. This PL improves with annealing and also with the layer thickness, up to a factor 4 when the thickness is increased from few tens to more than 1.3 µm.The origin of this behaviour seems to lie in some limiting factors related to the film thinness, such as barriers for nucleation and growth of sensitizers (Si‐ncs), stresses affecting the onset of phase separation and then the formation of Si‐ncs. To favour the growth of Si‐ncs in films as thin as tens of nm, the increase of the amount of Si excess was found to be necessary to enhance the Er PL through an increase of the density of Si‐ncs and, therefore, the coupling with Er ions. Such an enrichment with Si offers an additional advantage of favouring the injection and transport of carriers by electrical excitation (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Single step electrodeposition process using ionic liquid to grow highly luminescent silicon/rare earth (Er, Tb) thin films with tunable composition

“…RE incorporated Si materials are widely used for applications in telecommunication, 5 photovoltaics 6,7 and display applications such as electroluminescence 8,9 or Light Emitting Diodes (LEDs). 10 A great number of techniques have been developed to incorporate the RE ions into silicon, such as ion implantation, 11 magnetron co-sputtering 12,13 and plasma enhanced chemical vapour deposition (PECVD). 14,15 However these current synthesis methods involve constraining deposition conditions such as high vacuum, high temperature, different steps of growth and the use of potentially dangerous precursors which makes these processes complicated and expensive.…”

High rectifying behavior in Al/Si nanocrystal-embedded SiOxNy/p-Si heterojunctions

“…The increase of the Si content would result in a higher nc-Si density for the thinnest SiO x N y -nc-Si layers. This assumption could be related to a higher fraction of clustered silicon, as observed in the thinnest sputter-deposited SiO x layers for thicknesses lower than 150 nm [23]. Quasi-static C-V measurements have been made to check the validity of the obtained permittivity values.…”