| Energy is the material basis of human activities,but as society continues to develop and progress,people are willing to develop and waste non-renewable energy,causing not only serious environmental pollution,global warming,but also the depletion of available energy.Researchers are committed to developing new energy materials and effectively improving energy utilization.The development and use of new energy sources depends on functional materials.Therefore,functional materials have become a hot topic in recent years.As one of the functional materials,the thermoelectric material is a material that can directly convert thermal energy from factories and power plants into electric energy without causing environmental pollution by using the Seebeck effect,realize waste heat reuse,and realize the Peltier effect.Thermoelectric cooling can also be achieved using the Peltier effect.The use of thermoelectric materials can not only improve energy efficiency,but also reduce environmental pollution.At the same time,thermoelectric devices have the advantages of small size,long life and safety,and are widely used in military,medical,transportation and other fields.Thermoelectric materials mainly include alloy materials and oxide materials.The thermoelectric materials widely used in practical life are mainly alloy materials,such as Bi2Te3,PbTe,etc.,which have good thermoelectric properties,but limit their large-scale application due to problems such as containing toxic heavy metal elements.Oxide thermoelectric materials have the advantages of high temperature performance,simple preparation process,no toxicity,low cost,etc.,but they are not able to meet the needs of practical applications.Therefore,researchers have tried to improve the thermoelectric properties of materials by doping.In this paper,the n-type oxide thin film thermoelectric material TiO2 was selected as the research object.The effect of ion beam implantation of Nb on its crystal structure and thermoelectric properties was investigated,and treated in a high temperature reducing environment.,the TiO2 film still maintained the rutile structure and studied different treatments.Conditions for the electrical and thermal transport properties of materials to improve the application value of thermoelectric devices in real life.The specific content of this paper works as follows:1.The TiO2 films with a thickness of about 80 nm was epitaxially grown on a(0001)oriented single crystal Al2O3 substrate by PLD method.XRD phase analysis The(200)and(400)crystal plane diffraction peaks of rutile TiO2 appeared at 39.19°and 84.27°,respectively.Nb doping in rutile TiO2 films by ion implantation was carried out.The TiO2 film samples with Nb friction doping concentration of 6.0 at.%calculated at room temperature has the highest power factor of 0.62 mW/m·K2 after two hours of reduction at a temperature of 1473K,which is higher than the room temperature power factor of the high temperature reduction polycrystalline bulk about12 times.It is indicated that the Nb element doping and high temperature reduction treatment at the appropriate dynamic annealing temperature by ion beam implantation can effectively improve the thermoelectric properties of the rutile TiO2 films.2.The characteristic peaks observed in the Raman spectrum correspond to the four Raman-active vibration modes of the rutile-type TiO2.PPMS measures its thermoelectric properties in the temperature range of 50-380 K,and exhibits semiconductor resistance behavior over the entire temperature range.,the transport operation of these samples is to better satisfy the small polaron conduction mechanism.The power factor value of the film samples with a doping concentration of 6.0%at 380 K can reach 1.0 mW/m·K2,which is about 19 times the power factor of the TiO2 polycrystalline bulk material prepared in the reducing atmosphere. |
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