Bogdan Firtat

The research proposes to obtain an optimized gas sensing system for monitoring very low concentration of pollutant and explosive gases to in domestic or industrial environments. The design, simulation, sensors fabrication and testing results are provided. The microsensors on nanostructured metal oxides (SnO2, ZnO, SnO2:ZnO, SnO2:ZnO:Fe2O3) have been fabricated and tested for CO, C3H8 and CH4 detection. Miniaturized IDT (interdigitated transducer) electrodes made on Ti(50 nm)/Au(150 nm)… Afișați mai multe

The research proposes to obtain an optimized gas sensing system for monitoring very low concentration of pollutant and explosive gases to in domestic or industrial environments. The design, simulation, sensors fabrication and testing results are provided. The microsensors on nanostructured metal oxides (SnO2, ZnO, SnO2:ZnO, SnO2:ZnO:Fe2O3) have been fabricated and tested for CO, C3H8 and CH4 detection. Miniaturized IDT (interdigitated transducer) electrodes made on Ti(50 nm)/Au(150 nm), patterned on the front side of a 0.2 mm thick alumina wafer have been fabricated. Sensitive coating consisting of different nanostructured metal oxides was deposited on the ITD’s, together with a Ti/Pt heater patterned on the back side of the alumina wafer. Working temperatures between 250 °C ÷ 550 °C can be reached by applying 15 V DC for 5–20 s. The chosen fabrication technology provides a reliable and low-cost sensing device. Afișează mai puține

The paper work has been focused on the technology development of an impedimetric microbiosensor
array for pesticides detection. The microbiosensors array is containing six biosensor chips
integrated into a microfluidic system providing all fluids for biosensors activation and inhibition,
electrically connected to electronic modules for signal processing and data acquisition.

The paper describes the design and functions of a miniaturized integrated platform for optical and electrical monitoring of cell cultures and the necessary steps in the fabrication and testing of a silicon microchip Micro ElectroMechanical Systems (MEMS)-based technology for cell data recording, monitoring and stimulation.

The paper work has been focused on the technology development of an impedimetric microbiosensor array for pesticides detection.

The paper describes the process of designing, modelling and simulating a multichannel implantable microprobe for neural cells recording and stimulation. The microprobe has a thin tip (3 mm long, 240 µm wide and 50 µm thick). The paper focuses on modelling the probe when inserted into the tissues (in vivo or in vitro), in order to prove its mechanical resistance against the forces exerted on insertion.

Due to the specific intrinsic limitations in developing standard fluidic channels, we are using 20 µm wide channels, but the protein solution must have a very narrow flow, in order to allow the specific protein adsorption on the FET nano-wire surface. In order to achieve this, we are using the hydrodynamic focusing technique, using two buffer channels that combine with the protein solution channel. For specific channels dimensions and flow rates, the protein solution will flow in a narrow… Afișați mai multe

Due to the specific intrinsic limitations in developing standard fluidic channels, we are using 20 µm wide channels, but the protein solution must have a very narrow flow, in order to allow the specific protein adsorption on the FET nano-wire surface. In order to achieve this, we are using the hydrodynamic focusing technique, using two buffer channels that combine with the protein solution channel. For specific channels dimensions and flow rates, the protein solution will flow in a narrow, laminar manner, focused by the buffer solutions. Afișează mai puține

Simulations of microfluidic devices are described, in order to determine so call “dead spots” within microfluidic devices (polymer microchannels with specific shapes). Continuous flow and also droplets-type flow (liquid bubbles) has been analyzed. The continuous flow modelling consisted in determining the fluid’s velocity for a specific range of flow rate, while the droplets-type flow focused on observing the movement of a fluid bubble through the microchannel. The microfluidic design was… Afișați mai multe

Simulations of microfluidic devices are described, in order to determine so call “dead spots” within microfluidic devices (polymer microchannels with specific shapes). Continuous flow and also droplets-type flow (liquid bubbles) has been analyzed. The continuous flow modelling consisted in determining the fluid’s velocity for a specific range of flow rate, while the droplets-type flow focused on observing the movement of a fluid bubble through the microchannel. The microfluidic design was performed using SolidWorks and the simulations were performed using the CoventorWare’s microfluidic module, using FEM models. The simulation results are aimed at improving the future microfluidic designs, in order to optimise them from the fluid’s velocity point of view. Afișează mai puține

The paper presents the layout and the technological steps for an interdigitated integrated capacitor used for gases detection. Silicon micromachining technology is applied for manufacturing the sensor substrate. The sensitive layer used is phthalocyanine (Pc) deposed by evaporation technique under high vacuum. The phthalocyanine derivatives are obtained by the same deposition technique. Considering the different sensitivities of phthalocyanines derivatives, we obtained different gas sensors… Afișați mai multe

The paper presents the layout and the technological steps for an interdigitated integrated capacitor used for gases detection. Silicon micromachining technology is applied for manufacturing the sensor substrate. The sensitive layer used is phthalocyanine (Pc) deposed by evaporation technique under high vacuum. The phthalocyanine derivatives are obtained by the same deposition technique. Considering the different sensitivities of phthalocyanines derivatives, we obtained different gas sensors. The copper phthalocyanine (CuPc), nickel phthalocyanine (NiPc) and iron phthalocyanine (FePc) have been investigated for NOx detection. The measurement of sensors for NOx and NO2 detection will be presented as gas concentration versus impedance. The microsensors testing structures deposited with phthalocyanines were investigated by impedance measurements in a vacuum chamber controlled by a gas analyser. The measurements were made at room temperature but a medium temperature is applied (<200 °C) after measurement, for cleaning the material in order to reuse the sensor. The sensor is integrated, MOS compatible, cheap, easy to be used and has a low power consumption. Afișează mai puține

A series of SnO 2–ZnO composite nanostructured (thin) films with different amounts of SnO 2 (from 0 to 50 wt%) was prepared and deposited on a miniaturized porous alumina transducer using the sol–gel and dip coating method. The transducer, developed by our research group, contains Au interdigital electrodes on one side and a Pt heater on the other side. The sensing films were characterized using SEM and AFM techniques. Highly toxic and flammable gases (CO, CO 2, CH 4, and C 3 H 8) were tested… Afișați mai multe

A series of SnO 2–ZnO composite nanostructured (thin) films with different amounts of SnO 2 (from 0 to 50 wt%) was prepared and deposited on a miniaturized porous alumina transducer using the sol–gel and dip coating method. The transducer, developed by our research group, contains Au interdigital electrodes on one side and a Pt heater on the other side. The sensing films were characterized using SEM and AFM techniques. Highly toxic and flammable gases (CO, CO 2, CH 4, and C 3 H 8) were tested under lab conditions (carrier gas was dry air) using a special gas sensing cell developed by our research group. The gas concentrations varied between 5 and 2000 ppm and the optimum working temperatures were in the range of 210–300 C. It was found that the sensing performance was influenced by the amount of oxide components present in the composite material. Improved sensing performance was achieved for the ZnO (98 wt%)–SnO 2 (2 wt%) composite as compared to the sensors containing only the pristine oxides. The sensor response, cross-response and recovery characteristics of the analyzed materials are reported. The high sensitivity (R S= 1.21) to low amounts of CO (5 ppm) was reported for the sensor containing a composite sensitive film with ZnO (98 wt%)–SnO 2 (2 wt%). This sensor response to CO was five times higher as compared to its response to CO 2, CH 4, and C 3 H 8, thus the sensor is considered to be selective for CO under these test conditions. Afișează mai puține