Jan J. Dubowski

Université de Sherbrooke | UdeS · Department of Electrical and Computer Engineering

Silicon (Si) is a widely used material by the very-large-scale integration technology addressing manufacturing of integrated electronic circuits. Micromachined Si has also shown its advantages in the fabrication of advanced microelectronic, photonic and micro-electro-mechanical system devices whose continuously decreasing dimensions present growing...

Photocorrosion of semiconductors is strongly sensitive to the presence of surface states, and it could be influenced by electrically charged molecules immobilized near the semiconductor/electrolyte interface. The underlying mechanism is related to band bending of the semiconductor structure near the surface and the associated distribution of excite...

Radiation from a 193 nm ArF laser was investigated to modify surface properties of InGaAs/InGaAsP quantum well (QW) heterostructures and introduce defects required to enhance intermixing during the annealing process. A top 200 nm thick sacrificial layer of InP served as a reservoir for laser generated defects. The irradiation with up to 90 pulses a...

We report on the basic properties of Cd1−xMnxTe and CdTeCd1−xMnxTe multilayer structures and superlattices grown by pulsed laser evaporation and epitaxy (PLEE). Two computer controlled XeCl and Nd:YAG lasers are used for simultaneous or sequential vaporization of high-purity polycrystalline targets. The layers are grown on (001) oriented InSb and...

Bacillus cereus is a spore-forming ubiquitous bacterium notable as a food poisoning agent. Detection of B. cereus spores using selective media is laborious and non-specific. Herein, the quantitative detection of B. cereus spores was investigated with commercial antibodies and published aptamer sequences. Several detection reagents were screened for...

Conventional etching techniques do not have the ability to achieve precision of monolayer etching of crystalline solid materials. In recent years, atomic layer etching (ALE) has emerged as a method addressing this challenge based on the application of self-limiting sequential reactions. Nevertheless, monitoring of the ALE process, important for rea...

Since Legionella pneumophila has caused punctual epidemics through various water systems, the need for a biosensor for fast and accurate detection of pathogenic bacteria in industrial and environmental water has increased. In this report, we evaluated conditions for the capture of live L. pneumophila on a surface by polyclonal antibodies (pAb) and...

Bacillus thuringiensis (Bt) is used as a bioinsecticide since it effectively kills insect larvae. Bt is also genetically similar to Bacillus cereus (Bc), a well recognized foodborne human pathogen; they are both members of the Bacillus cereus group (BC group). Although approved Bt bioinsecticide products have been confirmed to be non-pathogenic to...

We report the formation of extraordinary density 16-mercaptohexadecanoic acid (MHDA) self-assembled monolayer (SAMs) on surfaces of freshly etched and re-etched bulk (001) GaAs and on GaAs surfaces of a (001) GaAs/Al0.35Ga0.65 As nanoheterostructure exposed by digital photocorrosion (DIP). Our results demonstrate the advantage of a 2-step thiolatio...

A regenerable bulk acoustic wave (BAW) biosensor is developed for the rapid, label-free and selective detection of Escherichia coli in liquid media. The geometry of the biosensor consists of a GaAs membrane coated with a thin film of piezoelectric ZnO on its top surface. A pair of electrodes deposited on the ZnO film allows the generation of BAWs b...

Despite evidence showing that polymer brushes (PBs) are a powerful tool used in biosensing for minimizing nonspecific interactions, allowing for optimization of biosensing performance, and the fact that GaAs semiconductors have proven to have a remarkable potential for sensitive biomolecule detection, the combination of these two robust components h...

The detection of water contamination with Legionella pneumophila is of critical importance to manufacturers of water processing equipment and public health entities dealing with water networks and distribution systems. Detection methods based on polymerase chain reaction or biosensor technologies require preconcentration steps to achieve attractive...

Culture-based methods for the detection of Legion-ella pneumophila are prohibitively slow and frequently inadequate. The problem has been addressed with biosensing technology that employs a variety of ligands for the specific capture of bacteria. However, the limited success of the application of mammalian antibodies, aptamers, and nucleic acid-bas...

GaAs/AlGaAs semiconductor nanoheterostructures have found attractive application in the !eld of biosensing based on the e"ect of digital photocorrosion (DIP). The sensitivity of semiconductor−nanoheterostructure-based biosensors depends on the precision of controlling the process of DIP, which is highly sensitive to the surface presence of electric...

© Springer Nature Switzerland AG 2020 K. Sugioka (ed.), Handbook of Laser Micro- and Nano-Engineering, https://doi.org/10.1007/978-3-319-69537-2_29-1 The continuous progress in advancing thin films growth methods has enabled fabrication of innovative devices based on semiconductor microstructures. The epitaxial growth techniques, such as molecular...

The continuous progress in advancing thin films growth methods has enabled fabrication of innovative devices based on semiconductor microstructures. The epitaxial growth techniques, such as molecular beam epitaxy, chemical beam epitaxy, metal-organic chemical vapor deposition and numerous derivatives of these techniques have made the films and micr...

Digital photocorrosion (DIP) of GaAs/AlGaAs nanoheterostructures has been found sensitive to semiconductor surface states and, thus, attractive for rapid detection of negatively charged bacteria in aqueous environment. However, calibration of DIP biosensors depends on the reproducibility of chip-to-chip surface properties that are related to the ch...

An understanding of the inter-species relationships, especially their metabolic network in a mixed-culture system, is crucial to design an effective inoculum for enhancing the power generation of wastewater fed microbial fuel cell (MFC). In the present study, the influence of microbial mutualistic interactions on the power generation of palm oil mi...

This work reports the deposition and characterization of piezoelectric ZnO thin films on semi-insulating GaAs substrates for the fabrication of bulk acoustic waves sensors. ZnO films are deposited at 350 °C and low deposition rate using reactive radio frequency magnetron sputtering. The use of a Pt bottom electrode, between ZnO and GaAs, with and w...

The spontaneous electron transfer between GaAs and ionic gold through the galvanic displacement reaction results in formation of gold nanoparticles and Au9Ga4 alloy. We investigated this process for decorating Legionella pneumophila and Escherichia coli aiming at enhanced imaging of these bacteria. The surface of bacteria was modified with gold ion...

Detection of pathogenic Legionella pneumophila by culture-based methods is not efficient in predicting outbreaks of the Legionnaires’ disease. The main problem is the relatively slow time-to-result and the inability of some culture media to support the growth of viable bacteria. One strategy to alleviate these issues is developing biosensors functi...

The net electric charge associated with a bacterial strain is primarily defined by the number of available functional groups at its surface and we observed that it can determine the limit of detection of a charge sensing biosensor. We have investigated the dynamic range of bacterial electric charge variations through binding negatively charged sodi...

In recent years, transition metal complexes have been developed for catalytical degradation of a phosphate ester bond, particularly in RNA and DNA; however, less consideration has been given for development of complexes for the degradation of a phosphorothioate bond, as they are the foremost used pesticides in the environment and are toxic to human...

This thesis was conducted in the frame of an international collaboration between Université de Bourgogne Franche-Comté in France and Université de Sherbrooke in Canada. It addresses the development of a miniaturized biosensor for the detection and quantification of bacteria in complex liquid media. The targeted bacteria is Escherichia coli (E. coli...

Photo atomic layer etching (photo-ALE) of GaAs and AlGaAs semiconductors was investigated in deionized H2O and aqueous solution of NH4OH under weak excitation conditions (P  20 mW/cm2). The process is based on digital photocorrosion in a processed solution and a negligible corrosion during the light-off phase employed for dissolution of the photoc...

The development of organic molecules to target nucleic acid is an active area of research at the interface of chemistry and biochemistry, which involves DNA binding, nuclear imaging, and antitumor studies. These molecules bind with DNA through covalent interactions, electrostatic interactions, or intercalation. However, they are less permeable to m...

It has been known that GaAs and AlGaAs could be decomposed in aqueous environments and, if irradiated with photons of energy exceeding bandgap of these materials, their decomposition accelerates through a well-known photocorrosion process. The sensitivity of photoluminescence (PL) of semiconductors to the presence of surface states has been investi...

Fabrication of devices based on semiconductor multilayer structures demands routine measurement of thicknesses and location of the interfaces of the constituent layers. This is often achieved using expensive and complicated techniques such as scanning electron microscopy, secondary ion mass spectroscopy, atomic force microscopy (AFM) or x-ray photo...

Antibiotic resistant bacteria have become a threat to world health. An advanced method of detection, based on matrix assisted laser desorption ionization time-of-flight mass spectroscopy can identify bacteria relatively rapidly, but it is not suitable to measure bacterial antibiotic resistance. Biosensors may be able to detect resistance by monitor...

Controlling the emission wavelength of quantum dots (QDs) over large surface area wafers is challenging to achieve directly through epitaxial growth methods. We have investigated an innovative post growth laser-based tuning procedure of the emission of self-assembled InAs QDs grown epitaxially on InP (001). A targeted blue shift of the emission is...

Fluorescent zinc complexes of 1,2-disubstituted benzimidazole(R1-R3) have been synthesized and characterized using single crystal XRD. The ligands L1-3were found to be less emissive due to photoinduced electron transfer (PET) mechanism originated from the electron pair of benzimidazole nitrogen.The complexation of ligands with Zn(II) not only enhan...

A photo-electrochemical bio-sensor uses a semiconductor heterostructure located in an etching solution. An outer layer of the heterostructure is functionalized, such as with a self-assembled monolayer, to provide adherence of a charged molecule of interest. When contacted by a test solution, the functionalization immobilizes a quantity of the molec...

Nanostructuring of semiconductor wafers with an atomic level depth resolution is a challenging task, primarily due to the limited availability of instruments for in situ monitoring of such processes. Conventional digital etching relies on calibration procedures and cumbersome diagnostics applied between or at the end of etching cycles. We have deve...

Controlling the emission wavelength of quantum dots (QDs) over large surface area wafers is challenging to achieve directly through epitaxial growth methods. We have investigated an innovative post growth laser-based tuning procedure of the emission of self-assembled InAs QDs grown epitaxially on InP (001). A targeted blue shift of the emission is...

Growth and antibiotic sensitivity of Escherichia coli were evaluated with an innovative method based on photocorrosion of biofunctionalized GaAs/AlGaAs quantum well (QW) biochips. The formation of surface oxides and dissolution of a limited thickness GaAs cap material results in the appearance of a characteristic maximum in a time-dependent plot of...

We report on the formation kinetics of mixed self-assembled monolayers (SAMs) comprising 16-mercaptohexadecanoic acid (MHDA) and 11-mercapto-1-undecanol (MUDO) thiols on GaAs(100) substrates. These compounds were selected for their potential in constructing highly selective and efficient architectures for biosensing applications. Molecular composit...

Detection of pathogenic bacteria and monitoring their susceptibility to antibiotics are of great importance in the fields of medicine, pharmaceutical research, as well as water and food industries. In order to develop a photonic biosensor for detection of bacteria by taking advantage of photoluminescence (PL) of GaAs-based devices, we have investig...

The papers in this volume were part of the technical conference cited on the cover and title page. Papers were selected and subject to review by the editors and conference program committee. Some conference presentations may not be available for publication. Additional papers and presentation recordings may be available online in the SPIE Digital L...

Monitoring the viability, growth and cellular metabolism of bacteria can contribute significantly to the early diagnosis of disease, but can also help improve yield of bacterial products in industrial- or small-scale experiments. Conventional methods applied for investigation of antibiotic sensitivity of bacteria are mostly culture-based techniques...

High sensitivity of the photoluminescence (PL) effect to surface states and chemical reactions on surfaces of PL emitting semiconductors has been attractive in monitoring photo-induced microstructuring of such materials. To address the etching at nano-scale removal rates, we have investigated mechanisms of photocorrosion of GaAs/Al0.35Ga0.65As hete...

Cette thèse porte sur l'élaboration d'un biocapteur, à bas coût, pour la détection de pathogènes dans les secteurs de l'agroalimentaire et de l'environnement. Le modèle visé est la bactérie Escherichia coli, dont les souches pathogènes sont responsables, chaque année, de plusieurs crises sanitaires. L'utilisation de biocapteurs pour une détection r...

Les besoins croissants dans différents domaines et dans de nombreuses situations, de donner une information en temps réel sur la présence d‘un organisme biologique dans un environnement spécifique, ont motivé le développement d‘une multitude de technologies de détection. Ces technologies se regroupent sous le terme de « biocapteur », outil de mesur...

Semiconductor microstructures comprising stacks of GaAs/AlGaAs layers have found attractive applications for photocorrosion-based detection of electrically charged molecules immobilized in the vicinity of their surfaces. We have investigated sensitivity of the photocorrosion of GaAs/AlGaAs microstructures with a stack of 30 GaAs quantum well (QW) l...

Development of quick and reliable methods to investigate antibiotic susceptibility of bacteria is vital to prevent inappropriate and untargeted use of antibiotics and control the antibiotic resistance crisis. The authors have developed an innovative, low-cost and rapid approach to evaluate antibiotic susceptibility of bacteria by employing photolum...

We have examined the influence of electrical bias on immobilization of bacteria on the surface of GaAs/AlGaAs heterostructures, functionalized with an alkanethiol based architecture. A mixture of biotinylated polyethylene glycol (PEG) thiol and hexadecanethiol was applied to attach neutravidin and antibodies targeting specific immobilization of Leg...

We have examined the influence of electrical bias on immobilization of bacteria on the surface of GaAs/AlGaAs heterostructures, functionalized with an alkanethiol based architecture. A mixture of biotinylated polyethylene glycol (PEG) thiol and hexadecanethiol was applied to attach neutravidin and antibodies targeting specific immobilization of Leg...

Wet chemical processes were investigated to remove alkanethiol self-assembledmonolayers(SAMs) and regenerate GaAs (001) samples studied in the context of the development of reusable devices for biosensing applications. The authors focused on 16-mercaptohexadecanoic acid (MHDA) SAMs that are commonly used to produce an interface between antibodies o...

Publication of record for individual papers is online in the SPIE Digital Library. SPIEDigitalLibrary.org Paper Numbering: Proceedings of SPIE follow an e-First publication model. A unique citation identifier (CID) number is assigned to each article at the time of publication. Utilization of CIDs allows articles to be fully citable as soon as they...

This paper investigates a high sensitive piezoelectric sensor in Gallium Arsenide (GaAs) crystal for biological molecules detection in liquid environment. The lateral field excitation was used to generate bulk acoustic waves (BAW) through (001) GaAs membranes. The crystallographic plane and the electric field orientation were chosen to obtain the h...

We report on the fast wavelength switching in V-cavity laser (VCL) with quantum well intermixed tuning section. The laser wavelength can be switched between 32 channels at 100 GHz spacing using a single electrode control. The fabrication process involves a quantum well intermixing (QWI) process using KrF laser irradiation and rapid thermal annealin...

The wettability of silicon (Si) is one of the important parameters in the technology of surface functionalization of this material and fabrication of biosensing devices. We report on a protocol of using KrF and ArF lasers irradiating Si (001) samples immersed in a liquid environment with low number of pulses and operating at moderately low pulse fl...

Compact and portable surface plasmon resonance (SPR) biosensors of high sensitivities can be made through integration of discrete components in a single device. We report on a device comprising a vertical cavity light emitting diode (VLED) integrated with gold-based biosensing nanostructures fabricated atop its surface. Coupling of surface plasmon...