Armenian science potential in Semiconductor Chemical Sensors and Solar Cells made of Nanostructures and commercialization proposals Vladimir AROUTIOUNIAN ArmTech 2 Congress October 4, 2008, Panel II Yerevan, Armenia

Yerevan State University DEPARTMENT OF PHYSICS OF SEMICONDUCTORS & MICROELECTRONICS and RESEARCH CENTER OF SEMICONDUCTOR DEVICES AND NANOTECHNOLOGIES (Faculty of Radiophysics) 40 students per year 2 PhD students per year Participation in teaching of 12 students per year for SYNOPSYS-ARMENIA 12 Professors, Docents and Ass.-Professors 24 Researchers

TECHNOLOGIES Ceramics Thin Films Evaporation (thermal, plasma assisted, magnetron etc.) Liquid-, Electroliquid & “Step - Cooling” Liquid Phase Epitaxy. Sol-gel Growth of Single Crystal, Multi- and Nanocrystalline as well as Porous Semiconductors Nanoparticles and Nanograins

SCIENTIFIC ACTIVITY: Main directions today SILICON, INCLUDING NANO&MICROPOROUS SILICON. 3-5 SEMICONDUCTORS (InAs, InAsP, InAsP etc.). GRADED BANDGAP SEMICONDUCTORS. SILICON CARBIDE. DIAMOND LIKE CARBON. INFRARED, MAGNETO- and UV DETECTORS. INJECTION PHENOMENA. NOISE QUANTUM-SIZE EFFECTS IN SEMICONDUCTORS. NANOSCALE PHYSICS,TECHNOLOGY AND ELECTRONICS THERMOELECTRICITY SEMICONDUCTOR INTERFACE with DIFFERENT MEDIA. SEMICONDUCTOR METALOXIDES. CHEMICAL SENSORS CONVERSION of SOLAR ENERGY into HYDROGEN, HEAT and ELECTRICITY

METAL OXIDE PHOTOELECTRODES FOR HYDROGEN PHOTOELECTROCHEMICAL GENERATION An increase in the efficiency of conversion of solar energy into hydrogen is realized by the deviation from stoichiometry of stable in water electrolytes metal oxides ( TiO 2-x etc.) or appropriate doping of n-type oxides with different impurities. Best results in world in the efficiency, but not enough for large scale applications. Photoelectrodes made of n-and p-type single crystalline, thin films and nanotubes. Synthesis of new semiconductor phases made of solid solutions of wide band gap oxide (more than 3 eV) and rather small band gap oxide (corresponding to the maximum of the solar radiation spectrum).

Photoelectrolysis setup (one from 4 versions) Unique in the world  Photoelectrolysis setup with compound parabolic - cylindrical concentrator: 1- body of PECell 2 - quartz windows; 3 - semiconductor matrix; 4 – electrolyte; 5-ion-exchanging membrane; 6-parabolic-cylindrical concentrator.

TiO2 nanotubes

Photoelectrical Conversion of Solar Energy Multilayer Antireflection Coatings for Silicon Solar Cells Nano porous silicon, diamond, silicon oxinitride etc. thin films –YSU+ P.Soukiassian (Saclay, France). Covered by 2 French Patents Reflectance spectrum of DLC/PS (solid line) and SiO2/TiO2 double layer ARCs (dash-dotted line )

CONVERSION OF SOLAR ENERGY TO ELECTRICITY BY PHOTOVOLTAIC AND THERMO PHOTOVOLTAIC CELLS THERMO PHOTOVOLTAIC CELLS (YSU) made of InP-InAs System. Graded-bandgap photodiodes and position-sensitive detectors made of 3-5 semiconductors grown in YSU by liquid and electroliquid epitaxy [V. Aroutiounian, K. Gambaryan, V. Gevorgyan (now in Russ-Slavonic Univ. Yerevan)]. Quantum dot nanocrystalline solar cells [ Aroutiounian, A. Khachatryan, S. Petrosyan (now in Russ-Slavonic Univ. Yerevan), and K. Touryan (USA); A. Kechiyants (Inst. For Radio Phys. & Electronics, NAN, Ashtarak)] and other nanoscale photodevices QD cells proposed in YSU in 2000 and realized in Japan in SELF–ASSEMBLED InAsSbP - BASED STRAIN INDUCED ISLANDS ON InAs SUBSTRATES AND SAW THEIR EVOLUTION FROM PYRAMIDS TO QUANTUM DOTS Now we have first experimental samples with QDs grown un YSU (K. Gambaryan). We realized SELF–ASSEMBLED InAsSbP - BASED STRAIN INDUCED ISLANDS ON InAs SUBSTRATES AND SAW THEIR EVOLUTION FROM PYRAMIDS TO QUANTUM DOTS “SOLAREN” (V. Afiyan) and “TRANSISTOR” (A. Vardanyan) produced in small scale solar panels using silicon solar cells made out of Armenia. STUA are working on covering of Si solar cells with diamond like carbon ARC (J. Panosyan)

Investigation of Optical and Photoelectric Properties of Semiconductor-Liquid Crystal Interface Improve the Time Characteristics of the Semiconductor-Liquid Crystal System Based Electrooptical Devices by using Interface Controlled Effect Increasing of Giant Optical Nonlinearity (GON) by using semiconductors as a substrate in Liquid Crystal cells Manufacture of new type of devices based on this effect (H. Margaryan)

CHEMICAL SENSORS and GAS DETECTORS Besides residential applications, gas and fire detectors are used under operating conditions at fossil as well as nuclear power plants, in fuel cells in order to prevent different type incidents. It is necessary to have аn information about the concentration of hydrogen, methane, carbon monoxide and dioxide as well as other gases and humidity in order to prevent false alarm. Research and development of world class semiconductor metal-oxide adsorptive sensing elements (with micro-and nano size of sensitive grains) for different gases made of different metaloxide semiconductors as well as integral components of new type sensors and detectors or non-expensive Hybrid Multisensor Security System for the market are carrying out in YSU

Hydrogen and CO Sensors Development and investigation of corresponding technologies and regimes for obtaining of relatively thermally stable nano- sized SnO 2 particles of very small dimensions and thin films on its base. The sensitivity of gas sensors strongly depends on nanocrystallites’ smallness. Weak dependence of grains size on films calcinations temperature found. Low operating temperatures and consumed electric power are typical for our sensors. The sizes of nanoparticles measured using TEM shows that offered by us technique ensures more stability of grain sizes (in comparison with known techniques). The SnO 2 grains remained less than 6 nm even after the calcinations at 750 o C. Hydrogen sensors were manufactured both for multisensor e- nose array and fuel cell hydrogen leak warning. We are planning to develop new sensors for different gases and use Synopsys tools to design of corresponding cheap e- nose for home and office defence.

Different materials such as semiconducting oxides (Sn0 2, ZnO, TiO 2, Fe ), catalytic oxides (V 2 O 5, MoO 3, CuO, NiO), metals deposited on oxide supports (Pt/Sn0 2, Pt/ZnO, Pd/SnO 2 ), and mixed (or complex) oxides exhibit different physical properties on exposure to different gas species. Even though the semiconductor oxides used for gas sensors are catalytically active, a small amount of a catalytic metal or metal oxide is often added to improve their selectivity and sensitivity. Main investigators in YSU in the field of metal oxide semiconductors are now Z. Adamyan, V. Arakelyan, Kh. Martirosyan, G. Shahnazaryan, A. Adamyan, Z. Mkhitaryan, V. Galstyan, G. Stepanyan, E. Khachaturyan, H. Asriyan etc. First 4 scientists and V. Aroutiounian got the Prize of President of Armenia for investigations in

The sensor sample packed in TO-5 case Teflon carrier The contacts with golden wire thermocompression bonding

H 2 sensitivity vs. operating temperature

Another type hydrogen gas sensor working without pre-heating of work-body is proposed in collaboration with Prof. P. Soukiassian and shown in Figure. Pt catalytic layer and Au electrical contacts were deposited by ion-beam sputtering on metal oxide thin film which prevent porous silicon sensitive layer from oxidation. All types of sensors are covered by patents.

Noise spectroscopy of gas sensing

Fire & Smoke Detectors Fire detection and registration at the early stages has always been an extremely important problem. It is concerned with, primarily, guarantees of safety of human life and health, pre-serving buildings and constructions as well as environment ecology. New, absorption type smoke detectors with cheap semiconductor sensitive chip are developed by us. Detectors are covered by several patents including the US one. Recently we successfully partly tested our detectors in Southwest Research Institute (San Antonio, USA). Regretfully, we had not the amount for full testing. Our detectors’ cost and size are much lower than they for photoelectrical and radioactive ionization detectors, which are today in the market.

Most relevant applications of the Products Bi2O3 adsorptive type smoke and NOx sensors (Patented in Armenia, the first modification was Patented in US) The Product is most effective at fire detection in early stages of smoldering and can be extremely useful in multi-sensor solutions in Home security systems and e - noses Other applications Dwelling houses and apartments, hotels, hospitals. Specialized installations: a. Military and civil warehouses, depot, aircrafts hangars, plant facilities. b. Elevator (wells) and communication lines shafts of high-rise buildings, underground communication lines, subway systems. Aircrafts and ships Ecologic monitoring of environment *) *) The product is applicable for environmental monitoring in large cities, where the motor transport concentration is high, and in industrial cities for air monitoring with the object to monitor the norm excess content of SOx and NOx gases. It can provide ecological monitoring of environment in system of “electron nose” on high altitudes in mountainous regions and in intensive areas of pass of Wind Rose. It can also work without fail at autonomously energy supply to function in sensor net system for early fire warning in large forest tracts. Such companies as Invensys Sensor Systems and NOTIFIER - Fire Alarm Systems and Technology were considered by IC2 Institute technology assessing teams as potential partners for future commercialization of the product.

Most relevant applications of the Products Nanocrystalline SnO2 thin-films based sensors for Hydrogen and CO detection (Patented in Armenia); the product is developed under DOE funding. Porous silicon – metal oxide tandem nanostructures for Hydrogen and other hazardous gases sensing including CO (Patented in Armenia) Hydrocarbon Gas and Methane Nanosensors made of ZnO and other metal oxides (Know - how) The key advantage of such low cost nanosensors are high sensitivity and workability of the sensing element nearby room temperatures, possibilities to realize multi-sensor solution made on single crystal chipset platform. Applications: Hydrogen propelled/integrated critical infrastructure and autonomous systems monitoring Home security systems, E-noses Fuel cells Security multi-sensor solutions Environment monitoring systems Gas pipelines monitoring systems The key advantage of the Product is able to detect Hydrogen and various Hazardous gases with controlled sensitivity In our opinion Honeywell International Inc. can foster patentable potential in this product upgrade. Local market is considered as the most effective investment zone for large-scale production of such nanosensors. Most relevant applications of the Products

The non-military world market for sensors exceeded expectations with US $ 32.5 billion in Up to 2003, this market growed at an annual rate of 5.3% reaching up to US $ 42.2 billion. In 2008 the global sensor market volume could even reach US $ 54 billion. The world sensors market is expected to reach US $ 61.4 billion by Sensor types with the highest demand volumes worldwide are temperature sensors, pressure sensors, flow sensors, binary position sensors (proximity switches, light barriers, reflectortype photosensors), position sensors, chemical sensors for measurement in liquids and gases, filling sensors, speed and rpm-sensors, flue gas sensors and fire detectors. The fastest growing types of sensors include rain sensors, thickness sensors, sensors that measure the quality of liquids, navigation sensors, tilt sensors, photodetectors, glass breakage sensors, biosensors, magnetic field sensors, and motion detectors.

World Market for Sensors

Human resourses Yerevan State University 40 students are graduated annually in the fields of Radio physics, Microelectronics and Semiconductor Physics. Research Center of Semiconductor Devices and Nanotechnologies is working now. State Engineering University of Armenia 40 students are graduated annually in the fields of Radio electronics and Circuitry Russian-Slavonic University 20 students are graduated annually in the field of Semiconductor electronics

All mentioned above materials, photoelectrodes, cells, sensors and setups were made in our Department in YSU. Several modern technological equipment and measurement setups were purchased in the framework of our International grants. We have about 40 Patents (including the USA, France, Russian Federation, USSR and Armenia ones) and are authors of several hundreds publications in West countries and USSR’ journals as well as in Proceedings of International Conferences and Meetings. Several conferences were organized by us in Armenia. About 100 citations of our papers were made by foreign scientists in leading journals only in 4 last years.

Now we are waiting for new names of peoples and companies who can help us to correctly organize the commercialization and production (preferable in Armenia) of proposed and realized by us samples of new type smoke and gas detectors, photoelectrolysis cells and thermo photovoltaic devices as well as antireflection coatings for silicon solar cells and to help us in the realization of our promising nanoscale devices!!!