Synthesis and Characterization of High c-axis ZnO Thin Film by Plasma Enhanced Chemical Vapor Deposition System and its UV Photodetector Application

We offered a method to directly synthesize high c-axis (0002) ZnO thin film by plasma enhanced chemical vapor deposition. The as-synthesized ZnO thin film combined with Pt interdigitated electrode was used as sensing layer for ultraviolet photodetector, showing a high performance through a combination of its good responsivity and reliability.

The overall goal of this procedure is to synthesize a high C axis zinc oxide thin film by plasma enhanced chemical vapor deposition and use the as synthesized film combined with a platinum interdigitated electrode as a sensing layer for an ultraviolet photo detector device. This is accomplished by first using a plasma enhanced chemical vapor deposition system to synthesize the high C axis zinc oxide thin film onto a silicon one oh oh substrate under the optimum synthesis parameters. The second step is to manufacture the interdigitated pattern onto the zinc oxide thin film surface by conventional optical lithography in a clean room.

Next radiofrequency magnetron sputtering is used to deposit a thin, conductive platinum layer on the top of the zinc oxide thin film, and then the sample is immersed in acetone in an ultrasonic cleaner. To remove the photo resist, the final step is to perform a rapid thermal, a kneeling process for obtaining an omic contact interface between the platinum electrode and the zinc oxide thin film. Ultimately, the realtime photo current response measurement is used to show a fast responsivity and high reliability under the UV light.

The main advantage of this technique over existing methods like conventional chemical vapor deposition is led lower synthesis temperature, high expect ratio condition is available, good surface infirmity high deposition rate, and the chemical conversation of nano scale structures can be highly controlled. This present plasma enhanced chemical vapor definition technique provides a master for preparing the ZI sizing theme onto silicon substrates and can also be applied to the formation of other functional materials onto more fretful substrates, such as guine and other two dimensional layered materials onto mite substrates. First cut 10 millimeter by 10 millimeter silicon substrates from a silicon one oh oh wafer.

Use an ultrasonic cleaner to clean the silicon substrates with acetone for 10 minutes, ethyl alcohol for 10 minutes and isopropanol for 15 minutes. When finished, rinse the substrates with deionized water three times. Then blow dry the substrates with a nitrogen gun.

Next, set the working distance between the shower head electrode and sample stage at 30 millimeters. Place the substrates on the sample stage of the reaction chamber so that they are three centimeters from the dathyl zinc inlet. Open the rotary pump and gradually open the gate valves and butterfly valve.

After the background pressure of the reactor chamber is lower than 30 milit to close the gait valves and butterfly valve, which connects to the rotary pump. Then open the turbo pump and relative gait valves to reach a high vacuum of three times 10 to the minus six tor. The ion gauge filament will be lighted for detecting high vacuum.

After reaching necessary vacuum condition, open the heat controller and heat the sample stage to the synthesis temperature. When the temperature and pressure reach the necessary conditions, close the turbo pump and then open the gate valves and butterfly valve connected to the rotary pump simultaneously. Next, open the gas inlet valves and turn on the Argonne gas flow controller.

Simultaneously flow the Argonne gas to 10 SCCM into the chamber. Set the chamber pressure to 500 milato. Turn on the RF generator and matching network.

Then set the RF power at 100 watts for purging the sample surface for 15 minutes. At the same time, the plasma generated in the chamber shows a plumb color. After purging the samples, turn the RF power down to 70 watts.

Turn on the carbon dioxide gas controller and gas inlet valve. Next, flow the carbon dioxide at 30 SCCM into the chamber. Set the working pressure at six tor.

At the same time, the plasma color will change to white. After the chamber pressure reaches six tor flow the high pure Argonne as carrier gas at 10 SCCM for carrying dathyl zinc into the chamber and open the ball valve connected to the dathyl zinc simultaneously. At the same time, start the synthesis of the zinc oxide films.

At the same time, the plasma color will change to blue after the zinc oxide films have been synthesized. Sirium turnoff the RF generator ball valve heat controller, and all of the gas flow controllers along with gas inlet valves. Then remove the sample when the sample stage temperature cools down to room temperature.

At this point, place the as fabricated platinum zinc oxide sample into a rapid thermal annealing or RTA system. Use the mechanical pump and gait valve to pump down the RTA chamber pressure to 20 militar. After waiting until the chamber pressure reaches 20 millitorr flow argon gas at 0.3 milliliters per second into the chamber and set the working pressure to five tor.

Next, set the heating rate to 100 degrees Celsius per minute, ane the sample at 450 degrees Celsius for 10 minutes. After allowing the Anil sample to cool to room temperature, remove it from the chamber. X-ray diffraction indicates that the film synthesized at 400 degrees Celsius had the strongest oh oh oh two diffraction peak when the temperature increased to 500 degrees Celsius.

The oh oh oh two diffraction peak became weaker with the appearance of a 1 0 1 bar. Oh diffraction peak in C two optical emission spectroscopy indicates that emission peaks for zinc, oxygen, carbon monoxide, and some decomposition species of dathyl zinc were detected. During synthesis feel the emission scanning electron microscopy images reveal that the zinc oxide thin films show different surface morphologies with different synthesized temperatures.

The film synthesized at 300 and 400 degrees Celsius show a strong near band edgy mission and a negligible deep leveling mission in the photo luminescence spectra. In addition, the near band edgy mission shifts to a low wavelength with increasing temperature. The transmittance measurement shows that the zinc oxide thin films synthesized at 200, 300 and 400 degrees Celsius have good transparency with an average visible transmittance higher than 80%The IV curves are symmetric reflecting an MSM omic contact behavior between the film and platinum electrode.

The platinum combined with zinc oxide UV photodetector shows a fast responsivity and high reliability with over five times turning, switching on and off circles at a bias of five volts. This plasma enhanced chemical vapor deposition technique path, the way for the researchers in the field of material science and the physics to study this presented optical electronic zinc outside base materials for potential applications such as UV photo detector and the multifunctional sensor. After watching this video, you should have a good understanding of how to completely synthesize link oxide fins by plasma enhanced chemical vapor.

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