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Method for reducing phase change temperature of vanadium dioxide film

A vanadium dioxide, phase transition temperature technology, applied in chemical instruments and methods, heat exchange materials, coatings, etc., can solve the problem of high phase transition temperature, achieve lower phase transition temperature, good optical properties, and excellent optical properties Effect

Inactive Publication Date: 2015-03-25
WUHAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Undoped vanadium dioxide thin films have quite high infrared modulation efficiency, but the phase transition temperature is much higher than room temperature

Method used

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  • Method for reducing phase change temperature of vanadium dioxide film
  • Method for reducing phase change temperature of vanadium dioxide film
  • Method for reducing phase change temperature of vanadium dioxide film

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Take an undoped M-phase vanadium dioxide thin film prepared by an inorganic sol-gel method and measure the thermal hysteresis loop of the film at 2000 nm. The phase transition temperature of the film is measured to be 64.7°C, and the thermal hysteresis loop width is 13°C. Such as figure 1 The solid line shown is the thermal hysteresis loop measured at 2000 nm for the vanadium dioxide thin film prepared in advance. figure 2 The solid line shown in the figure is the transmission curve of the sample measured under the temperature conditions of 25°C and 90°C.

[0036] The sample is placed in a tube-type retreat furnace, evacuated to a vacuum degree of 2000 Pa, and the vacuum pump is continuously turned on to keep the vacuum degree unchanged.

[0037] The heating rate of the tubular annealing furnace is set to 5°C / min, and the temperature is raised to 300°C and kept for 3 hours. Then cool down with the furnace.

[0038] By measuring the thermal hysteresis loop of the undoped vana...

Embodiment 2

[0040] Take the tungsten-doped (1%) M phase vanadium dioxide thin film prepared by the inorganic sol-gel method, and measure the thermal hysteresis loop of the thin film at 2000nm (such as image 3 As shown by the solid line) and the transmission curve (as Figure 4 The solid line shown), the phase transition temperature of the film is 47.5°C, and the width of the thermal hysteresis loop is 22°C.

[0041] The operation steps are the same as those of the embodiment 1, and the process conditions of step 2) are: evacuating to a vacuum degree of 2000 Pa, and then passing Ar to normal pressure to maintain a relative vacuum. The process conditions of step 3) are that the heating rate is 5° C. / min, the temperature is increased to 310° C. and the temperature is kept for 3 hours, and the temperature is naturally cooled in an Ar atmosphere furnace after the temperature is completed.

[0042] By measuring the thermal hysteresis loop of the undoped vanadium dioxide film at 2000 nm, the phase tr...

Embodiment 3

[0044] Take the undoped M-phase vanadium dioxide thin film prepared by magnetron sputtering method, and measure the thermal hysteresis loop of the thin film at 2000nm (such as Figure 5 The solid line shown), the phase transition temperature of the film is 49°C, and the width of the thermal hysteresis loop is 23°C.

[0045] The operation steps are the same as those in Example 1, and the process conditions of step 2) are as follows: evacuating to a vacuum degree of 1000 Pa, and continuously turning on the vacuum pump to maintain a high vacuum. The process condition of step 3) is that the heating rate is 10°C / min, the temperature is increased to 320°C and the temperature is maintained for 2 hours, and the temperature is naturally cooled in the furnace after the temperature is completed.

[0046] By measuring the thermal hysteresis loop of the undoped vanadium dioxide film at 2000 nm, the phase transition temperature of the film is measured to be 43°C, and the width of the thermal hys...

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Abstract

The invention discloses a method for reducing the phase change temperature of a vanadium dioxide film. The method comprises the following steps: 1) preparing an M-phase vanadium dioxide film with a phase change function, wherein the M-phase vanadium dioxide film is formed on a substrate; 2) putting an M-phase vanadium dioxide film sample prepared in the step 1) into an annealing device, vacuumizing the annealing device till the vacuum degree is 200-2000 Pa, keeping the vacuum degree, or vacuumizing till the vacuum degree is 200-2000 Pa, subsequently introducing inert gas to the standard atmospheric pressure, heating to be 280-320 DEG C, keeping the temperature for 0.5-3 hours, and natural cooling to be the room temperature in a furnace, thereby obtaining the vanadium dioxide film with reduced phase change temperature. By adopting the method, the phase change temperature of a pure vanadium dioxide film can be reduced, and the phase change temperature of a doped vanadium dioxide film can also be reduced, so that the method has a very wide application range. In addition, the method is low in treatment temperature, simple in process, good in safety and wide in application prospect in the field of high-end photoelectric functional materials.

Description

Technical field [0001] The invention belongs to the technical field of functional film preparation, and in particular relates to a method for reducing the phase transition temperature of a vanadium dioxide film. Background technique [0002] Vanadium dioxide has semiconductor-metal phase transition (MIT) characteristics and is an intelligent thermochromic material. At 68℃, vanadium dioxide changes from a low-temperature monoclinic semiconductor phase to a high-temperature tetragonal metal phase. With the semiconductor-metal phase transition, its electrical, optical, and magnetic properties all undergo large reversible changes. Therefore, vanadium dioxide has very important application value in many fields such as smart energy-saving windows, infrared detection, optical switches, and optical storage. [0003] Powder or single crystal vanadium dioxide can cause the material to crack or become fragments after multiple phase changes. The vanadium dioxide thin film can still exist sta...

Claims

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Application Information

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IPC IPC(8): C03C17/23C04B41/50C09K5/06
CPCC03C17/23C03C2217/21C04B41/5072
Inventor 陶海征赵新宇赵修建
Owner WUHAN UNIV OF TECH
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