13-5-2013: Παρουσίαση του κύκλου
XXIX Panhellenic Conference on Solid State Physics and Materials Science, 22-25 September 2013, NTUA, Athens
Transparent Conductive Materials, TCM2012, 4th Int. Conference, Crete, 21-25 October 2012 (Group Photo)
Photovoltaics Seminar : "PV technology Development and Market Trends", NTUA, 4;5 October 2010, Athens.
MediterraneanTransnational Technology Transfer MET3
Technology Based Opportunities
50. Hydrogen Microsensor based on NiO (page 43)
The goal is the development of a sensing device for hydrogen, methane and carbon monoxide detection, based on NiO thin films grown by Pulsed Laser Deposition (PLD). The sensor will operate electrochemically; that is, the change of the electrical resistance of the semiconducting thin film will be the signal for the gas detection.
The growth of the thin films will take place at the LATA/NHRF laboratory. The device will consist of many layers, each of them performing a special task. First, the Pt micro-heater for the heating of the sensor will be deposited on the substrate. The significant improvement will be the incorporation of a micro-thermocouple for the measurement and control of the temperature which is a very important parameter for the proper operation of the sensor. The next layer will be for electrical isolation and on the top the NiO thin film grown by PLD. Metallic electrodes will be connected to the NiO thin film to pick up the signal indicating the gas detection.
Characteristics and Advantages
The operating temperature of the sensor is the most important parameter for its operation
sensitivity, response time, etc). For the design of the sensor, NiO was chosen as the sensing material which will be grown by an innovative 2 lasers/2 targets PLD method. The best response at H2 has been measured with the thin film sensor grown at 400 C, with gold nanoparticles embedded into the NiO matrix. The operating temperature was as low as 80 C, while the goal is to reduce even more the operating temperature, achieving even environmental temperature (RT).
At such low temperatures, the chemical activity of the surface of the semiconductor is reduced. In order to balance this, noble metal Au nanoparticles will be implanted into the NiO matrix. The 2 lasers/2 targets technique has the unique advantage to optimize the parameters of the catalysts (nanoparticles material and concentration). Thus far, the advantages of the nanocomposite NiO gas sensor which has been grown at the LATA/NHRF laboratory are:
Low energy consumption (refering to the heating of the sensor)
Short pre-heating time before use (for stabilization)