| 1. |
- Hosseini, M., et al.
(författare)
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ISFET immunosensor improvement using amine-modified polystyrene nanobeads
- 2018
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Ingår i: Journal of Solid State Electrochemistry. - : Springer New York LLC. - 1432-8488 .- 1433-0768. ; 22:10, s. 3161-3169
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Tidskriftsartikel (refereegranskat)abstract
- Antigen-based sensing is recognized as a rapid and sensitive analysis among bioresearch groups. The potential of “on-site” analysis in such devices has been accompanied by some problems. Fabrication of silicon compatible and highly sensitive biosensors has been the center of excessive research within the past few years. In this paper, we report fabrication of two types of sensitive liquid oxide semiconductor (LOS) biosensors using nanostructures. These devices have been manufactured and characterized as immunosensors. These two types of sensors have been produced using different platforms for immobilization of proteins; one based on a functionalized silicon dioxide surface by 3-aminopropyltriethoxysilane (APTES) and another on the basis of using 50-nm amine-modified polystyrene nanobeads. The polystyrene platform not only benefits from its nanosize and high surface to volume ratio but also does not need any new protocol than what is already used for traditional immunosensing system. These sensors measure the change of threshold voltage of the semiconductor inversion inside the capacitor due to the bonding of antibodies to the linked peptides on the surface. Measurements showed that the sensitivity of 50-nm polystyrene-based sensor is much more than the oxide-based one. The nanobeads were then chosen to cover the gate of the ISFET for the amplified sensing. The ISFET devices were biased in a subthreshold region to demonstrate the maximum sensitivity to the accumulated charge on the gate. Repeatable results after different stress tests were obtained, which proves the suitability and reliability of the polystyrene nanobead platform for this application. Finally, a calibration curve has been derived that can be used for real sample measurements. The detection limit of 1.0152 μg/ml was calculated for the fabricated sensor. [Figure not available: see fulltext.].
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| 2. |
- Kermaniha, M., et al.
(författare)
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Systematic optimization of phosphorous diffusion for solar cell application
- 2016
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Ingår i: Journal of materials science. Materials in electronics. - : Springer-Verlag New York. - 0957-4522 .- 1573-482X. ; 27:12, s. 13086-13092
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Tidskriftsartikel (refereegranskat)abstract
- Fossil fuel storage is running low and scientists around the globe are involved in a big search for an optimized substitute. Photovoltaic is one of the most likely alternatives to solve this issue and replace the fossil fuels. Among all types of cells, silicon solar cells are the most economical ones to produce affordable energy. In this paper, a systematic study was done on the diffusion of phosphorous in multi-crystalline silicon during solar cell emitter formation. All parameters involved in the conversion of a multi-crystalline p-type silicon to a p-n junction were analyzed quantitatively. This systematic approach predicts the effect of inputs on the outputs which decreases the number of the trail runs. The analysis result indicate, that raising the diffusion temperature from 830 to 880 A degrees C decreases the sheet resistance by -100 Omega/sq, and increasing POCl3 flow from 300 to 500 SCCM has an effect of -21 Omega/sq.
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| 3. |
- Ebrahimi, P., et al.
(författare)
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Systematic Optimization of Boron Diffusion for Solar Cell Emitters
- 2017
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Ingår i: Journal of Electronic Materials. - : Springer. - 0361-5235 .- 1543-186X. ; 46:7, s. 4236-4241
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Tidskriftsartikel (refereegranskat)abstract
- To achieve p-n junctions for n-type solar cells, we have studied BBr3 diffusion in an open tube furnace, varying parameters of the BBr3 diffusion process such as temperature, gas flows, and duration of individual process steps, i.e., predeposition and drive-in. Then, output parameters such as carrier lifetime, sheet resistance, and diffusion profile were measured and statistically analyzed to optimize the emitter characteristics. Statistical analysis (factorial design) was finally employed to systematically explore the effects of the set of input variables on the outputs. The effect of the interactions between inputs was also evaluated for each output, quantified using a two-level factorial method. Temperature and BBr3 flow were found to have the most significant effect on different outputs such as carrier lifetime, junction depth, sheet resistance, and final surface concentration.
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| 4. |
- Fischer, Andreas C., et al.
(författare)
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Layer-by-layer 3D printing of Si micro- and nanostructures by Si deposition, ion implantation and selective Si etching
- 2012
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Ingår i: 12th IEEE Conference on Nanotechnology (IEEE-NANO), 2012. - : IEEE conference proceedings. - 9781467321983 ; , s. 1-4
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Konferensbidrag (refereegranskat)abstract
- In this paper we report a method for layer-by-layer printing of three-dimensional (3D) silicon (Si) micro- and nanostructures. This fabrication method is based on a sequence of alternating steps of chemical vapor deposition of Si and local implantation of gallium (Ga+) ions by focused ion beam (FIB) writing. The defined 3D structures are formed in a final step by selectively wet etching the non-implanted Si in potassium hydroxide (KOH). We demonstrate the viability of the method by fabricating 2 and 3-layer 3D Si structures, including suspended beams and patterned lines with dimensions on the nm-scale.
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| 5. |
- Norouzi, M., et al.
(författare)
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Thermoelectric energy harvesting using array of vertically aligned Al-doped ZnO nanorods
- 2016
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Ingår i: Thin Solid Films. - : Elsevier. - 0040-6090 .- 1879-2731. ; 619, s. 41-47
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Tidskriftsartikel (refereegranskat)abstract
- Renewable energy harvesting is an innovative research area which has attracted a great deal of efforts to find a substitute for fossil sources. This work presents processing and characterization of thermoelectric device (one leg of the nanogenerator) made of aluminum-doped zinc oxide (ZnO) nanorods on the glass substrate. The effect of aluminum-doping on the Seebeck coefficient as an important figure-of-merit for thermoelectric performance has been extensively studied. The electrical characterization was performed to examine the quality of the nanorods' contacts. For 1% Al-doped ZnO nanorods on the silicon substrate, open circuit voltage of 0.28 mV and S.C. current of 3.5 mu A were obtained. In these measurements, a constant temperature difference of 1 K between the top and bottom side of the nanorods was implemented. The Seebeck coefficient was found to be increased proportionally with the doping concentration.
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| 6. |
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| 7. |
- Kolahdouz, M., et al.
(författare)
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The influence of Si coverage in a chip on layer profile of selectively grown Si1-xGex layers using RPCVD technique
- 2008
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 517:1, s. 257-258
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Tidskriftsartikel (refereegranskat)abstract
- The influence of chip layout (Si coverage and geometry) on the pattern dependency of selective epitaxy of SiGe layers has been investigated. The variation of Ge content and the growth rate have been investigated from a chip-to-chip (local effect) or wafer-to-wafer. The results are described by transport and diffusion of the reactant molecules over the chips during epitaxy. Our investigations are focused on the origin of pattern dependency of the deposition and also propose methods to control this growth behavior.
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| 8. |
- Kolahdouz, Z., et al.
(författare)
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Substrate engineering for Ni-assisted growth of carbon nano-tubes
- 2012
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Ingår i: Materials Science & Engineering. - : Elsevier BV. - 0921-5107 .- 1873-4944. ; 177:17, s. 1542-1546
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Tidskriftsartikel (refereegranskat)abstract
- The growth of carbon multi-walled nano-tubes (MWCNTs) using metal catalyst (e.g. Ni, Co, and Fe) has been extensively investigated during the last decade. In general, the physical properties of CNTs depend on the type, quality and diameter of the tubes. One of the parameters which affects the diameter of a MWCNT is the size of the catalyst metal islands. Considering Ni as the metal catalyst, the formed silicide layer agglomerates (island formation) after a thermal treatment. One way to decrease the size of Ni islands is to apply SiGe as the base for the growth. In this study, different methods based on substrate engineering are proposed to change/control the MWCNT diameters. These include (i) well-controlled oxide openings containing Ni to miniaturize the metal island size, and (ii) growth on strained or partially relaxed SiGe layers for smaller Ni silicide islands.
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| 9. |
- Majdi, Saman, et al.
(författare)
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High Performance Temperature Sensors using SC-CVD Diamond Schottky Diodes
- 2012
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Ingår i: Applied Physics Letters. - 0003-6951 .- 1077-3118.
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Tidskriftsartikel (refereegranskat)abstract
- The synthesis of new materials for thermal IR detection has been an intensive research area during the recent years. Among the new materials, diamond has the ability to function under high temperature, high power, and high radiation conditions, which enables large performance enhancements to a wide variety of systems and applications, e.g. electric vehicles, space exploration and nuclear energy reactors. In this study, diamond Schottky diodes (with boron concentrations in the range 1×1015 - 3×1016 cm-3) are presented as candidates for IR sensors with an excellent temperature coefficient of resistance (-16 %/K) and noise levels around 1.8×10-14 (V2/Hz).
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| 10. |
- Soleimanzadeh, R., et al.
(författare)
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Ultra-high efficiency piezotronic sensing using piezo-engineered FETs
- 2018
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Ingår i: Sensors and Actuators A-Physical. - : Elsevier. - 0924-4247 .- 1873-3069. ; 270, s. 240-244
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Tidskriftsartikel (refereegranskat)abstract
- A large piezoelectric effect in the c-axis of Zinc Oxide (ZnO) nanorods (NRs) which are vertically aligned to the gate of an nMOSFET is demonstrated. A controlled mechanical pressure was applied to create piezoelectric polarization in the structure and induce charges in the transistor's channel. The resultant piezo-induced charges could modulate the electrostatics of the transistor channel and sense the pressure. ZnO NRs were grown using hydrothermal and microwave-assisted methods and the piezoelectric quality of each one was evaluated. The NRs grown by sequential microwave–assisted growth demonstrated the optimum response. An induced piezo-potential as large as 3.5 V was measured on the transistor's gate when a vertical force of 1.5 N (10 MPa) was applied to the array of NRs and the corresponding piezoelectric coefficient of 66 pC/N was calculated. Such a large enhancement in the piezoelectricity (five-fold increase compared to ZnO thin films) attributes to the high crystal quality of the ZnO NRs, high mechanical flexibility, as well as low potential loss at the electrical contacts of the NRs to the device.
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