microwave-assisted low-temperature growth of thin films in solution
by：Taian Lamination Film2020-10-07
There are a wide range of technical applications for film. Assembling the film from atoms in the liquid phase is essentially a non- Equilibrium Phenomena controlled by competition between thermodynamics and dynamics. We demonstrate here that microwave energy can help to assemble atoms directly into thin films at a much lower temperature than conventional processes, which may make plastic- Based on electronics. Experimental and electro-magnetic simulation results show that although there are differences between substrate size and microwave wavelength, the microwave field can selectively interact with the conductive layer on the substrate. Microwave interactions lead to local energy absorption, heating, and subsequent nuclear and growth of the required film. Emc simulations show significant consistency with experiments and are used to understand the physical properties of microwave interactions and to determine the conditions for improving film uniformity. These films can be patterned and grown on different substrates, thus being able to be used in a wide range of applications. Tin oxide (ITO) Coating glass substrate and conductivity σ ~ 10 m/s/m are purchased from Nanocs (New York, NY) Cut from 1 cm² square to 1 cm². Low conductivity (σ ~ 10u2005S/m) ITO coated glass substrates are equipped by 3-in. InO: SnO (10u2005wt. % SnO) Sputtering target (99. Kurt J. purity 99%Lesker company). The ITO film is grown from a 75 w rf power supply with an Ar working pressure of 3 mmtorr and a basic pressure of 8. 75 × 10 Torr 60 min. In a typical process, the ITO layer is 75% de- Ionised water, 20% HCl and 5% HNO. And then with de- Ionize water and clean by continuous ultrasound in detergent In the flowing nitrogen, the water, acetone and acetone, which are ionised, are finally dried. Deposited Al film (σ ~ 10u2005S/m) On a clean glass substrate, achieved through a thermal evaporation process, the use of high-purity aluminum wire is carried out in a vacuum of about 10 Tors (99. 9995%) Hanging on a tungsten basket By controlling the deposition current and time, the thickness of the Al film is controlled at 15 nm. Some experiments were also conducted on ITO. PET substrate coated with Nanocs ( Conductivity σ ~ 10 m/s/m). A sol- As previously reported, a gel solution based on the tetramine acid of N-titanium acid was prepared. In general, sol-5 ml- 20 ml gel and Sigan alcohol (TEG) In the 80 ml quartz container designed for 2. An dongpa 45 GHz Synthos 3000 microwave reactor. The substrate is placed in a glass basket of custom design, and the glass basket is suspended at the top of the container. Most experiments are performed on vertically aligned substrates, but there are also experiments that are performed on horizontally aligned substrates. To ensure efficient mixing and container sealing, a mixing rod was added. The vessel is then placed on the rotor ( Up to 8 ships at a time) Rotate on the turntable so that the microwave radiation is uniform. The heating rate, temperature and reaction time are different. The temperature is measured by an infrared sensor on each container. After the reaction, the solution cooled to room temperature, and the resulting TiO film was de- Ionize water, acetone and ethanol to remove impurities such as TEG. In this work, the Anton pal Monowave microwave was also used. In 10 ml SiC and glass containers, ITO- Coated glass substrates are hung on the top of the vessel with a custom basket tied to the ship\'s cap with Teflon tape. The reaction temperature is measured directly in the growth solution by a thermometer immersed inside the tube. In these reactions, the thermometer is located directly behind the glass substrate. In about 3 minutes, the temperature rises to 160 °c and remains for 60 minutes. More details are given inside. Incidence of sweeping X Ray diffraction (GIXRD) The experiment was performed with rigultima IV diffraction operated in parallel beams (PB) Mode using cuk α radiation at 40kv and 44 ma (λ = 1. 54 Å) In the range of 2 theta from 20 to 80 °, at 0 steps. 02 ° and glancing angle 0. 5°. Scanning electronic microscopic photos (SEM) Fei Guangda 650 has been used for scanning electron microscope observation. Film thickness obtained by Cross Segmented SEM imaging. Atomic force microscope (AFM) The image was taken on the Agilent 5500 AFM. Conductive AFM (C-AFM) The contact information of the image is conductive ( Aluminum-plated silicon) The tip and 3 µV apply an electrical bias to the surface of the sample. Therefore, the circuit inside the AFM can measure the current flowing when the tip is in contact with the surface of the sample. Here, we use C- At the same time map the AFM image of microwave terrain TiO thin films grown with regions where conductivity changes. Transmission electron microscope with low magnification scanning (STEM) Got the image on Hitachi S-5500. High resolution transmission electron microscopy (TEM) The image was obtained on JEOL 20f and worked for 200f thousand electron volts. For STEM and TEM analysis, the 5mm x 5mm part of TiO film was scraped off the ITO substrate and then dispersed in acetone by ultrasonic treatment for 5 min. This suspended small equal sample was collected on Lacey carbon mesh and dried overnight under vacuum. The Raman spectra obtained by Renishaw inVia Raman microscopy were performed at 50% of 50 mw 514. Laser excitation at 5 nm at 50 x target. Get the optical microscope with Nikon Eclipse ME600 optical microscope. Conductivity of the film (ITO, metal) Use four- Probe conductivity measurement system including Lucas Signatone four- Point probe head and bracket combined with Keithley 2400 Source table. Accelerate frequency using fast Fourier transform-domain integro- The glass substrate is modeled as a differential equation solver for ideal non-destructive dielectric materials, and the ITO layer is modeled as imperfect (but good) Conductor, as a liquid solution with a loss medium, as a quartz container for another non-destructive medium, and as a microwave reactor containing a cavity of a rotor with a perfect conductive wall. Hybrid roll- The surface integral equation formula is used to calculate the microwave fields at different positions of the rotor, and these fields are processed to obtain the energy absorbed at different positions in the model; The control equation and its numerical solution are introduced in detail.