ORCID Profile
0000-0003-1247-6914
Current Organisation
University of South Australia
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Publisher: Springer Science and Business Media LLC
Date: 09-01-2018
DOI: 10.1038/S41467-017-02564-3
Abstract: It is known that self-assembled molecular monolayer doping technique has the advantages of forming ultra-shallow junctions and introducing minimal defects in semiconductors. In this paper, we report however the formation of carbon-related defects in the molecular monolayer-doped silicon as detected by deep-level transient spectroscopy and low-temperature Hall measurements. The molecular monolayer doping process is performed by modifying silicon substrate with phosphorus-containing molecules and annealing at high temperature. The subsequent rapid thermal annealing drives phosphorus dopants along with carbon contaminants into the silicon substrate, resulting in a dramatic decrease of sheet resistance for the intrinsic silicon substrate. Low-temperature Hall measurements and secondary ion mass spectrometry indicate that phosphorus is the only electrically active dopant after the molecular monolayer doping. However, during this process, at least 20% of the phosphorus dopants are electrically deactivated. The deep-level transient spectroscopy shows that carbon-related defects are responsible for such deactivation.
Publisher: Springer Science and Business Media LLC
Date: 02-2017
DOI: 10.1038/SREP41299
Abstract: Doping via self-assembled macromolecules might offer a solution for developing single atom electronics by precisely placing in idual dopants at arbitrary location to meet the requirement for circuit design. Here we synthesize dendrimer-like polyglycerol macromolecules with each carrying one phosphorus atom in the core. The macromolecules are immobilized by the coupling reagent onto silicon surfaces that are pre-modified with a monolayer of undecylenic acid. Nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) are employed to characterize the synthesized macromolecules and the modified silicon surfaces, respectively. After rapid thermal annealing, the phosphorus atoms carried by the macromolecules diffuse into the silicon substrate, forming dopants at a concentration of 10 17 cm −3 . Low-temperature Hall effect measurements reveal that the ionization process is rather complicated. Unlike the widely reported simple ionization of phosphorus dopants, nitrogen and carbon are also involved in the electronic activities in the monolayer doped silicon.
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C005340F
Publisher: Optica Publishing Group
Date: 2021
DOI: 10.1364/CLEO_AT.2021.AW3T.7
Abstract: Absorption spectroscopy is demonstrated with microfluidic devices using collimating graded-index fibers. The optofluidics setup allows for absorption measurements to be performed with 10x smaller volumes than for standard cuvettes but with comparable sensitivity.
Publisher: The Electromagnetics Academy
Date: 2017
DOI: 10.2528/PIER17120504
Publisher: IEEE
Date: 12-2010
Publisher: SPIE
Date: 10-10-2012
DOI: 10.1117/12.940757
Publisher: American Chemical Society (ACS)
Date: 14-03-2022
Publisher: American Scientific Publishers
Date: 11-2008
DOI: 10.1166/JNN.2008.232
Publisher: American Chemical Society (ACS)
Date: 18-02-2019
Publisher: Springer Science and Business Media LLC
Date: 03-08-2022
DOI: 10.1007/S00542-022-05350-4
Abstract: Injection moulding of micropillar arrays offers a fast and inexpensive method for manufacturing sensors, optics, lab-on-a-chip devices, and medical devices. Material choice is important for both the function of the device and manufacturing optimisation. Here, a comparative study of poly(methyl methacrylate) (PMMA) and cyclic olefin copolymer (COC) injection moulding of micropillar arrays is presented. These two polymers are chosen for their convenient physical, chemical, and optical properties, which are favoured for microfluidic devices. COC is shown to replicate the mould’s nano/microstructures more precisely than PMMA. COC successfully forms a micropillar array (250 mm diameter 496 mm high) and closely replicates surfaces with nano-scale roughness (30–120 nm). In the same moulds, PMMA forms lens arrays (not true pillars) and smoother surfaces due to the incomplete filling for all parameters studied. Thus, COC offers finer structural detail for devices that require micro and nano-structured features, and may be more suited to injection moulding microfluidic devices.
Publisher: IEEE
Date: 30-10-2022
Publisher: Royal Society of Chemistry (RSC)
Date: 2011
DOI: 10.1039/C1CP21450K
Publisher: Elsevier BV
Date: 02-2007
Publisher: AIP Publishing
Date: 19-04-2010
DOI: 10.1063/1.3404183
Abstract: In this paper we report on the light emitting properties of mesoporous silicon vertical-cavity optical resonators with II-VI colloidal quantum dots selectively deposited in the cavity layer. Optical resonator structures exhibit reflectivity stop bands of several hundred nanometres and resonant modes with line-widths less than 3.5 nm. The observed modification of spectral and spatial emission properties of the quantum dots and tenfold enhancement at the resonance wavelength is consistent with cavity enhanced spontaneous emission. Using this hybrid fabrication approach we show that narrow band light emitting structures may be fabricated over a broad spectral region in the visible and near-infrared.
Publisher: American Chemical Society (ACS)
Date: 03-12-2020
Publisher: American Chemical Society (ACS)
Date: 09-12-2011
DOI: 10.1021/LA102599M
Publisher: MDPI AG
Date: 29-05-2022
DOI: 10.3390/S22114135
Abstract: The rapid development of optofluidic technologies in recent years has seen the need for sensing platforms with ease-of-use, simple s le manipulation, and high performance and sensitivity. Herein, an integrated optofluidic sensor consisting of a pillar array-based open microfluidic chip and caged dye-doped whispering gallery mode microspheres is demonstrated and shown to have potential for simple real-time monitoring of liquids. The open microfluidic chip allows for the wicking of a thin film of liquid across an open surface with subsequent evaporation-driven flow enabling continuous passive flow for s ling. The active dye-doped whispering gallery mode microspheres placed between pillars, avoid the use of cumbersome fibre tapers to couple light to the resonators as is required for passive microspheres. The performance of this integrated sensor is demonstrated using glucose solutions (0.05–0.3 g/mL) and the sensor response is shown to be dynamic and reversible. The sensor achieves a refractive index sensitivity of ~40 nm/RIU, with Q-factors of ~5 × 103 indicating a detection limit of ~3 × 10−3 RIU (~20 mg/mL glucose). Further enhancement of the detection limit is expected by increasing the microsphere Q-factor using high-index materials for the resonators, or alternatively, inducing lasing. The integrated sensors are expected to have significant potential for a host of downstream applications, particularly relating to point-of-care diagnostics.
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2CP43461J
Abstract: Herein, mesoporous silicon (PSi) is configured as a single sensing device that has dual readouts as a photonic crystal sensor in a Rugate filter configuration, and as a high surface area porous electrode. The as-prepared PSi is chemically modified to provide it with stability in aqueous media and to allow for the subsequent coupling of chemical species, such as via Cu(I)-catalyzed cycloaddition reactions between 1-alkynes and azides ("click" reactions). The utility of the bimodal capabilities of the PSi sensor for monitoring surface coupling procedures is demonstrated by the covalent coupling of a ferrocene derivative, as well as by demonstrating ligand-exchange reactions (LER) at the PSi surface. Both types of reactions were monitored through optical reflectivity measurements, as well as electrochemically via the oxidation/reduction of the surface tethered redox species.
Publisher: Elsevier BV
Date: 02-2021
Publisher: American Chemical Society (ACS)
Date: 03-07-2013
DOI: 10.1021/AM4006012
Abstract: Porous silicon (PSi) is an ideal platform for label-free biosensing, and the development of porous silicon patterning will open a pathway to the development of highly parallel PSi biochips for detecting multiple analytes. The optical response of PSi photonic crystal is determined by the changes in the effective bulk refractive index resulting from reactions/events occurring within the internal pore space. Therefore, introducing precise chemical functionalities in the pores of PSi is essential to ensure device selectivity. Here we describe the fabrication of PSi patterns that possess discrete chemical functionalities that are restricted to precise locations. The key difference to previous patterning protocols for PSi is that the entire porous material is first modified with a self-assembled monolayer of a α,ω-diyne adsorbate prior to patterning using a microfabricated titanium mask. The distal alkyne moieties in the monolayer are then amenable to further selective modification by the archetypal "click" reaction, the copper catalyzed alkyne-azide cycloaddition (CuAAC), using the titanium mask as a resist. This type of patterning is suitable for further immobilization of biological recognition elements, and presents a new platform for highly parallel PSi biosensor for multiple detections.
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2RA06740D
Abstract: Isolation of volatile analytes from fluid s les is a rate-determining step that can delay sensor response time. An optofluidic sensing platform capable of rapidly detecting gas-phase analytes from flowing micro-volume fluid s les is reported.
Publisher: American Chemical Society (ACS)
Date: 20-07-2012
DOI: 10.1021/JP303980X
Publisher: AIP Publishing
Date: 05-2011
DOI: 10.1063/1.3585782
Abstract: We report on the observation of significant optical bistability in the transmission and reflection properties of mesoporous silicon microcavities when illuminated with a 150 ns pulsed laser at 532 nm. The observed optical hysteresis is shown to be transient in nature and the properties are strongly dependent on the porosity of the cavity layer. The onset and damage threshold intensity are also shown to be porosity dependent. Our modeling suggests that the observed effects are due to changes in the nonlinear refractive index where the transient lifetime increases with increasing porosity. We investigate the role of surface states on influencing the bistable process by passivating the internal porous surface with hydrosilylation chemistry.
Publisher: American Chemical Society (ACS)
Date: 10-12-2019
Publisher: Royal Society of Chemistry (RSC)
Date: 2013
DOI: 10.1039/C3AN00081H
Abstract: Porous silicon photonics is the ideal platform for high sensitivity, high selectivity monitoring of biological molecules in a complex fluidic environment. The potential of this technology was identified almost 15 years ago, however, it has taken considerable advances in porous silicon surface chemistry, photonics, and micro-fabrication to create truly effective devices that can provide new insights into the behaviour of biological systems. In this review we provide a critical assessment of the development of porous silicon optical biosensors from the early demonstrations of affinity based sensing to the current trends in monitoring single cell activity and perspectives in the use of photonic microparticles for biomedical applications.
Publisher: American Chemical Society (ACS)
Date: 10-06-2014
DOI: 10.1021/BC500144U
Abstract: Herein, the ability of porous silicon (PSi) particles for selectively binding to specific cells is investigated. PSi microparticles with a high reflectance band in the reflectivity profile are fabricated, and subsequently passivated and modified with antibodies via the Cu(I)-catalyzed alkyne-azide cycloaddition reaction and succimidyl activation. To demonstrate the ability of the antibody-modified PSi particles to selectively bind to one cell type over others, HeLa cells were transfected with surface epitopes fused to fluorescent proteins. The antibody-functionalized PSi particles showed good selectivity for the corresponding surface protein on HeLa cells, with no significant cross-reactivity. The results are important for the application of PSi particles in cell sensing and drug delivery.
Publisher: Wiley
Date: 19-02-2020
Publisher: Elsevier BV
Date: 12-2019
Publisher: Optica Publishing Group
Date: 08-12-2021
DOI: 10.1364/BOE.414239
Abstract: This paper describes the design and characterization of miniaturized optofluidic devices for sensing based on integrating collimating optical fibers with custom microfluidic chips. The use of collimating graded-index fiber (GIF) tips allows for effective fiber-channel-fiber interfaces to be realized when compared with using highly- ergent standard single-mode fiber (SMF). The reduction in both beam ergence and insertion losses for the GIF configuration compared with SMF was characterized for a 10.0 mm channel. Absorption spectroscopy was demonstrated on chip for the measurement of red color dye (Ponceau 4R), and the detection of thiocyanate in water and artificial human saliva. The proposed optofluidic setup allows for absorption spectroscopy measurements to be performed with only 200 µL of solution which is an order of magnitude smaller than for standard cuvettes but provides a comparable sensitivity. The approach could be integrated into a lab-on-a-chip system that is compact and does not require free-space optics to perform absorption spectroscopy.
Publisher: American Chemical Society (ACS)
Date: 22-10-2012
DOI: 10.1021/LA303649U
Abstract: The ability to impart discrete surface chemistry to the inside and outside of mesoporous silicon is of great importance for a range of biomedical applications, from selective (bio)sensing to tissue-specific drug delivery. Here we present a generic strategy toward achieving depth-resolved functionalization of the external and internal porous surfaces by a simple change in the wavelength of the light being used to promote surface chemical reactions. UV-assisted hydrosilylation, limited by the penetration depth of UV light, is used to decorate the outside of the mesoporous structure with carboxylic acid molecules, and white light illumination triggers the attachment of dialkyne molecules to the inner porous matrix.
Publisher: Elsevier BV
Date: 12-2019
No related grants have been discovered for Bin Guan.