Ambient erbium luminescence in silicon and silicon-germanium films

Abstract

Prior studies have shown that photoluminescence from Er3+ impurities in silicon is severely limited at room temperature by non-radiative relaxation and solid solubility, and room temperature emission from Er3+ in oxide-based hosts becomes diminished at high erbium concentrations. This work presents studies of thin films (0·2 µm thick) prepared by vacuum co-evaporation from elemental sources (erbium, silicon and silicon/germanium) followed by vacuum annealing (600°C); materials of this type, which are produced with high Er3+ concentrations, are shown to be capable of yielding strong room temperature photoluminescence. Alloy films of Si–Er–O and Si–Ge–Er–O, containing (20 ± 2) at.% erbium and incorporating (16 ± 2) at.% oxygen (introduced by way of vacuum scavenging reactions), exhibit emission bands with dominant components at 1·51 and 1·54 µm (~0·04-µm overall spectral widths). Results are discussed in terms of erbium–oxygen complex formation and the effects of local randomness on cooperative inter-Er3+ energy transfer among thermal-broadened and local-field Stark-split 4I13/2→4I15/2 transitions. This paper discusses the advantages of scalability and low costs associated with producing optically active silicon-based materials.

Synthesis and Characterization of Erbium-Doped Silica Films Obtained by an Acid–Base-Catalyzed Sol–Gel Process

“…As was explained earlier, the 4f transitions possess some immunity from the host material and the overall symmetry, although the dominant peaks or preferred recombination transitions can vary. As a manifestation to this fact, we would like to bring the attention to the fact that the samples in this work were processed using sol-gel techniques, and that the transitions indicated on page 238 of reference [41] were for Er-doped aluminosilicate, while the ones in the work of Abedrabbo et al in references [42,43] were for ion beam mixing of Er, Si and O and for Er, Si, O and Ge, and all of them shared similar transitions. The ion beam mixing effort of this group started earlier without Er impurity centers as in references [44,45] and was consolidated with rare-earth inclusions.…”

Enhancing Photoluminescence Spectra for Doped ZnO Using Neutron Irradiation

“…In this study, gadolinium and iron were used as the implanted material. As a matter of fact, in addition to directly implanting Gd into ZnO as in this work, members of this group have been keeping a track record of ion-beam mixing coated samples to modify the bandgap of semiconductors as in refs ( 30 ) and ( 31 ) and to create structures with optically active impurity centers as in refs ( 32 ) and ( 33 ) via energetically accelerated inert gases.…”

Neutron Irradiation to Transmute Zinc into Gallium

“…Irradiation also allows for the investigation of fundamental semiconductor properties under extreme conditions in space applications. The group involved in this study has a long history of using irradiation as a technique, having previously performed ion-beam mixing to process modulated bandgap structures and surface modification of Si-substrates to introduce optically active impurities [23,24]. In the present work, we aim to demonstrate the alteration of optical properties in semiconductors through the transmutation of dopant constituents.…”