Room-temperature single-photon emitters in silicon nitride

Single-photon emitters are essential in enabling several emerging applications in quantum information technology, quantum sensing, and quantum communication. Scalable photonic platforms capable of hosting intrinsic or embedded sources of single-photon emission are of particular interest for the realization of integrated quantum photonic circuits. Here, we report on the observation of room-temperature single-photon emitters in silicon nitride (SiN) films grown on silicon dioxide substrates. Photophysical analysis reveals bright (>10⁵ counts/s), stable, linearly polarized, and pure quantum emitters in SiN films with a second-order autocorrelation function value at zero time delay g⁽²⁾(0) below 0.2 at room temperature. We suggest that the emission originates from a specific defect center in SiN because of the narrow wavelength distribution of the observed luminescence peak. Single-photon emitters in SiN have the potential to enable direct, scalable, and low-loss integration of quantum light sources with a well-established photonic on-chip platform.

Effect of argon flow on promoting boron doping for in-situ grown silicon nitride thin films containing silicon quantum dots

Boron-doped silicon nitride thin films (SiN_x) containing silicon quantum dots (Si QD) were prepared in situ by plasma enhanced chemical vapor deposition. With the aim of optimizing the performance of thin films, the mixed gas including argon and hydrogen was applied as dilution. The effects of Ar flow on the structural, electrical and optical properties of B-doped SiN_x thin films were systemically studied through various characterizations. By tuning the Ar flow, the properties, such as QD size, crystallinity and optical band gap, can be effectively controlled. The B-doping efficiency in thin films was proved to be promoted by introducing moderate Ar flow. The maximum values of dark conductivity (1.52 S cm^-1) and carrier concentration (2.41 × 10¹⁹ cm^-3) were obtained for the B-doped SiN_x thin films at the Ar flow of 200 sccm. Furthermore, the mechanism on the promotion in B-doping was illustrated in detail in this paper.

Plasma engineering of silicon quantum dots and their properties through energy deposition and chemistry

The authors growth and microstructure of a silicon quantum dot film by tailoring the plasma chemistry and deposition energy are studied.

Combined study of the effect of deposition temperature and post-deposition annealing on the photoluminescence of silicon quantum dots embedded in chlorinated silicon nitride thin films

The photoluminescence (PL) evolution of SiQDs respect deposition and annealing temperatures is studied in a combined manner. The PL identified changes are associated to changes in thin film composition. 150 °C is identified as an important threshold.

Self-assembled nc-Si-QD/a-SiC thin films from planar ICP-CVD plasma without H2-dilution: a combination of wide optical gap, high conductivity and preferred 〈220〉 crystallographic orientation, uniquely appropriate for nc-Si solar cells

Spontaneous miniaturization and rapid synthesis of self-assembled nc-Si-QDs of 〈220〉 orientation in high crystalline nc-Si-QD/a-SiC thin films of high conductivity and wide optical gap is obtained in ICP-CVD, from (SiH₄ + CH₄)-plasma, without H₂-dilution.

Low temperature synthesis of silicon quantum dots with plasma chemistry control in dual frequency non-thermal plasmas

The design of advanced plasma processes by plasma and radical control is essential for the controlled low-temperature deposition of different size QDs.

Linking photoluminescence of α-Si3N4 to intrinsic point defects via band structure modelling

Photoluminescence properties have been connected to intrinsic point defects for Si abundant (red bar) and N plentiful (blue bars) α-Si₃N₄via band structure modelling using DFT calculations.

Rapid synthesis of nc-Si/a-SiNx:H QD thin films by plasma processing for their cost effective applications in photonic and photovoltaic devices

A rapid and single step synthesis of nc-Si/a-SiN_x:H QD thin films has been made possible from a (SiH₄ + NH₃) gas mixture, with the advent of high density low pressure planar inductively coupled plasma processing.

Preferential 〈220〉 crystalline growth in nanocrystalline silicon films from 27.12 MHz SiH4 plasma for applications in solar cells

Si-ncs are generally of 〈111〉 crystal orientation from random nucleation within poly-H network at grain-boundary, while Si ultra-ncs preferably harvest 〈220〉 alignment due to thermodynamically preferred grain growth by mono-H bonding at the boundary.

Quantum size effects on the optical properties of nc-Si QDs embedded in an a-SiOx matrix synthesized by spontaneous plasma processing

An energy blue shift due to quantum confinement effects in tiny nc-Si QDs accompanied by larger Stokes shifts in PL at smaller dimensions.

Superior optical response of size-controlled silicon nano-crystals in a-Si:H/nc-Si:H superlattice films for multi-junction solar cells

In order to facilitate widening in optical band gaps utilizing quantum size-effects, self-assembled Si-ncs embedded in an a-Si matrix were grown within a-Si:H/nc-Si:H superlattice thin films produced by alternating sub-layers of a-Si:H and nc-Si:H.

Spectroscopic and microscopic studies of self-assembled nc-Si/a-SiC thin films grown by low pressure high density spontaneous plasma processing

In view of suitable applications in the window layer of nc-Si p-i-n solar cells in superstrate configuration, the growth of nc-Si/a-SiC composite films was studied, considering the trade-off relation between individual characteristics of its a-SiC component to provide a wide optical-gap and electrically conducting nc-Si component to simultaneously retain enough crystalline linkages to facilitate proper crystallization to the i-nc-Si absorber-layer during its subsequent growth. Self-assembled nc-Si/a-SiC thin films were spontaneously grown by low-pressure planar inductively coupled plasma CVD, operating in electromagnetic mode, providing high atomic-H density. Spectroscopic simulations of ellipsometry and Raman data, and systematic chemical and structural analysis by XPS, TEM, SEM and AFM were performed. Corresponding to optimized inclusion of C essentially incorporated as Si-C bonds in the network, the optical-gap of the a-SiC component widened, void fraction including the incubation layer thickness reduced. While the bulk crystallinity decreased only marginally, Si-ncs diminished in size with narrower distribution and increased number density. With enhanced C-incorporation, formation of C-C bonds in abundance deteriorates the Si continuous bonding network and persuades growth of an amorphous dominated silicon-carbon heterostructure containing high-density tiny Si-ncs. Stimulated nanocrystallization identified in the Si-network, induced by a limited amount of carbon incorporation, makes the material most suitable for applications in nc-Si solar cells. The novelty of the present work is to enable spontaneous growth of self-assembled superior quality nc-Si/a-SiC thin films and simultaneous spectroscopic simulation-based optimization of properties for utilization in devices.

Low temperature plasma processing of nc-Si/a-SiNx:H QD thin films with high carrier mobility and preferred (220) crystal orientation: a promising material for third generation solar cells

The nc-Si-QDs/a-SiN_x:H (∼5.7–1.3 nm) thin-films grown by low-temperature Inductively-coupled plasma, possess high carrier-mobility, electrical-conductivity, photosensitivity and preferred (220) crystal orientation, suitable for third-generation solar cells.