Preparation And Photoelectrochemical Water Splitting Properties Of InGaN Nanorods

The global dependence on fossil fuels and the increase of anthropogenic emissions of greenhouse gases make it necessary to develop clean and renewable energy in the future.Solar energy is one of the most promising renewable energy sources to solve the energy crisis and environmental pollution.Although solar energy can be absorbed and converted by using solar cells,this kind of photovoltaic equipment is limited by intermittent sunlight.Therefore,it is necessary to adopt new methods to store solar energy to meet the energy demand.Using solar energy to drive the decomposition of water is an effective way,because it can produce green hydrogen energy in a carbon free process.In this paper,the growth process of InN nanorods and InGaN nanorods was studied by using self-made halide chemical vapor deposition(HCVD)device,and the photoelectrocatalytic(PEC)water decomposition performance of the as prepared InGaN nanorods was tested and analyzed.The main results are as follows:(1)The controllable growth of InN micro-nanorods on Si(111)substrate was studied by HCVD method with indium trichloride as indium source and ammonia as nitrogen source.The effects of temperature of InCl₃ source region,NH₃ flow rate and N₂ carrier gas flow rate on the morphology and structure of InN nanorods were investigated.The results show that the nucleation rate and growth rate of InN nanorods can be improved with the increase of temperature in the source region of InCl₃.The NH₃ flow rate has an important influence on the crystal quality of InN nanorods.The appropriate NH₃ flow rate can meet the?/?ratio required for In source growth,and improve the quality of nanorods;when the NH₃ flow rate is too high,the formation of In vacancy defects make the crystal quality worse.N₂ carrier gas flow can affect the concentration and bias of In and N sources,which can effectively regulate the diameter and growth rate of InN nanorods.(2)On the basis of controllable preparation of InN nanorods,the growth and preparation of InGaN nanorods were carried out by adding gallium trichloride as gallium source.The effects of reaction temperature and the amount of Ga source on the morphology of InGaN nanorods were studied.Meanwhile,the water decomposition performance of the prepared InGaN nanorods by PEC was tested and analyzed.The results show that the increase of reaction temperature is conducive to the incorporation of Ga atoms.When the reaction temperature is too high,the decomposition of InN will reduce the growth rate and quality of crystal.The nucleation rate and specific surface area of InGaN nanorods were improved by increasing the amount of Ga source,but the nanorods merged with each other and the crystal mass was decreased by increasing the amount of Ga source.The photochemical test shows that,in addition to the composition,the defect density of InGaN nanorods will also affect the PEC performance.The nanorods will combine to introduce a large number of crystal defects,resulting in the recombination of photogenerated carriers,which will greatly reduce the photocurrent density.At the same time,the high density of surface states will lead to the pinning of Fermi level and the decrease of photovoltage.The stability test shows that the prepared InGaN nanorods have good photocorrosion resistance.In a word,the controllable preparation of InN nanorods with a diameter of 200 nm-1600nm was realized by using InCl₃ and GaCl₃ as raw materials,and the InGaN nanorods with a maximum Ga content of 23%were prepared.The photoelectrolyzed water test found that the increase in defect density is the main factor affecting the performance of photoelectrolyzed water,laying a foundation for further improving the efficiency of InGaN nanorod photoelectrolyzed water in the future.