Development Of Performance Characterization System For Infrared Emitting Metamaterials And Study On Device Stability

Infrared emitters based on layered metamaterials(LMM)have the advantages of adjustable emission wavelength and high radiation heat transfer efficiency.They have important applications in indoor and open space heating,infrared monitoring and other fields,which is currently a hot spot in the field of energy conservation and optoelectronics research.The current researches focus on the effects of LMM structure on its emission or absorption characteristics.However,there are few reports on the devices integrated with heating components,the practical performances related to electro-optical conversion(EOC)efficiency,stability and so on.In this paper,in order to meet the research needs of LMM infrared emitter integrated with electric heating films,a multifunctional characterization system with high precision EOC efficiency test and environmental control ability is designed and built based on vacuum technology.The system has improved control accuracy on input electric power,reduced heat conduction and heat exchange,and high accuracy on EOC efficiency test.In addition,the system can record and control various parameters of test samples and environment synchronously,providing comprehensive and accurate data for sample stability research and failure mechanism analysis.Then we use transfer matrix algorithm to carry out device design.LMM samples were prepared using electron beam evaporation method with integrated Ni Cr alloy electric heating film.The reflectance,transmittance,emission spectrum,emission rate of LMM infrared emitters were characterized comprehensively.Results show that the device can effectively restrain the emission of visible and near infrared light.Meanwhile,the device has a high emissivity of more than 0.8 in the middle and far infrared,much higher than W,Cr,Ni and other traditional metals.Finally,the EOC efficiency of the device was accurately measured based on the self-built system,and the failure mechanism was analyzed,leading to porposed methods for further improvement.Finally,to meet the requirements of LMM infrared emitter on electric heating film,three candidates for electric heating are proposed,which are platinum thick electrothermal film,tungsten electrothermal film,and heavily-doped low-resistance silicon wafer with thermally grown oxidizing layer,respectively.The feasibility of the three schemes was verified by the multi-parameter synchronous test capability of self-built system,combined with off-line SEM,XRD,and EDS measurements.Results show that the Pt thick film and W thin film is only suitable for backside heating coatings below 800°C due to the rough surface and low working temperature.The platinum thick film is easy to react with the substrate to form silicide while the W thin film is prone to be oxidized and fused higher than 800°C.The heavily-doped silicon wafer can work above 1000°C for a long time,and it can withstand high and low temperature impact.Furthermore,it has other advantages,such as smooth surface,low diffusing rate at high temperature,and deposition of LMM on both sides,which is considered as an ideal electric heating component for integrated metamaterial infrared emitters.