Shining a little light changes metal into semiconductor – Phys.org

Click here to sign in with or
Forget Password?
Learn more
share this!
Share
Twit
Share
Email
September 6, 2013
by Washington University in St. Louis
By blending their expertise, two materials science engineers at Washington University in St. Louis changed the electronic properties of new class of materials—just by exposing it to light.

With funding from the Washington University International Center for Advanced Renewable Energy and Sustainability (I-CARES), Parag Banerjee, PhD, and Srikanth Singamaneni, PhD, and both assistant professors of materials science, brought together their respective areas of research.
Singamaneni’s area of expertise is in making tiny, pebble-like nanoparticles, particularly gold nanorods. Banerjee’s area of expertise is making thin films. They wanted to see how the properties of both materials would change when combined.
The research was published online in August in ACS Applied Materials & Interfaces.
The research team took the gold nanorods and put a very thin blanket of zinc oxide, a common ingredient in sunscreen, on top to create a composite. When they turned on light, they noticed that the composite had changed from one with metallic properties into a semiconductor, a material that partly conducts current. Semiconductors are commonly made of silicon and are used in computers and nearly all electronic devices.
“We call it metal-to-semiconductor switching,” Banerjee says. “This is a very exciting result because it can lead to opportunities in different kinds of sensors and devices.”
Banjeree says when the metallic gold nanorods are exposed to light, the electrons inside the gold get excited and enter the zinc oxide film, which is a semiconductor. When the zinc oxide gets these new electrons, it starts to conduct electricity.
“We found out that the thinner the film, the better the response,” he says. “The thicker the film, the response goes away. How thin? About 10 nanometers, or a 10 billionth of a meter.”
Other researchers working with solar cells or photovoltaic devices have noticed an improvement in performance when these two materials are combined, however, until now, none have broken it down to discover how it happens, Banerjee says.
“If we start understanding the mechanism for charge conduction, we can start thinking about applications,” he says. “We think there are opportunities to make very sensitive sensors, such as an electronic eye. We are now looking to see if there is a different response when we shine a red, blue or green light on this material.”
Banerjee also says this same technology can be used in solar cells.

More information: Wu F, Tian L, Kanjolia R, Singamaneni S, Banerjee P. Plasmonic Metal-to-Semiconductor Switching in Au Nanorod-ZnO nanocomposite films. ACS Applied Materials & Interfaces. Dx.doi.org/10.1021/am402309x

Journal information: ACS Applied Materials and Interfaces
Provided by Washington University in St. Louis
Explore further
Facebook
Twitter
Email
Feedback to editors
17 hours ago
1
17 hours ago
0
18 hours ago
0
May 23, 2024
0
May 23, 2024
0
12 hours ago
13 hours ago
13 hours ago
14 hours ago
14 hours ago
14 hours ago
15 hours ago
15 hours ago
16 hours ago
16 hours ago
6 hours ago
May 22, 2024
May 14, 2024
May 11, 2024
May 10, 2024
May 8, 2024
More from Atomic and Condensed Matter
Aug 25, 2013
Mar 5, 2013
Aug 28, 2013
Jul 18, 2013
Aug 29, 2013
Jul 22, 2013
22 hours ago
May 22, 2024
May 21, 2024
May 20, 2024
May 17, 2024
May 16, 2024
Use this form if you have come across a typo, inaccuracy or would like to send an edit request for the content on this page. For general inquiries, please use our contact form. For general feedback, use the public comments section below (please adhere to guidelines).
Please select the most appropriate category to facilitate processing of your request
Thank you for taking time to provide your feedback to the editors.
Your feedback is important to us. However, we do not guarantee individual replies due to the high volume of messages.
Your email address is used only to let the recipient know who sent the email. Neither your address nor the recipient’s address will be used for any other purpose. The information you enter will appear in your e-mail message and is not retained by Phys.org in any form.

Get weekly and/or daily updates delivered to your inbox. You can unsubscribe at any time and we’ll never share your details to third parties.
More information Privacy policy
We keep our content available to everyone. Consider supporting Science X’s mission by getting a premium account.
Medical research advances and health news
The latest engineering, electronics and technology advances
The most comprehensive sci-tech news coverage on the web

source