Preparation Of Silicon Nanostructure And Its Application In Gas Sensors

Gas sensors are widely used because they can detect flammable and explosive gas,poisonous gas such as hydrogen,ammonia.Silicon nanowires are a new type of one-dimensional semiconductor materials,which have special optical and electrical properties.Compared with the ordinary silicon material,their optical properties are good,and are chemically active.They have more obvious advantages in practical application.So,gas sensors based on silicon nanostructures have good application prospect and have attracted the attention of some research scholars.There are many preparation methods of silicon nanostructure,mainly include: laser ablation method,template method,chemical vapor deposition(CVD),thermal evaporation,solution method and so on.In this study,silicon nanostructure films were synthesized by chemical vapor transport(CVT)in a high-temperature tube furnace.The experimental results showed that the silicon nanostructure films were made up of intertwined silicon nanorods.The length of the nanorods was in the micron range,and the diameter of nanorods was about 100 nm.Using the SEM and EDS characterization results of silicon nanostructure films,we analyzed the influence of the catalyst's thickness and substrate's location on silicon nanostructure films' growth.When the thickness of gold layer is thick,It is difficult to grow silicon nanostructure films.When the thickness of gold layer is about10 nm,it is easy to grow silicon nanostructure films.Through the SEM images,we know the silicon nanostructure films' morphology is related to the location of the substrate.Through the EDS patterns we know the main component of the sample is silicon.Using silicon nanostructure films,we successfully prepared a kind of gas sensor.We test the sensing properties in ethanol atmosphere and ammonia atmosphere.When the gas is ethanol,the higher the ethanol concentration,the bigger the response current is.When the gas is ammonia,the higher the bias,the bigger the response current is.We also found that the recovery time of the gas sensor is short and its repeatability is good.So we think the production process is simple,the cost is low,and they also have great value in practical application.