editor's blog
Subscribe Now

Piezo… what?

The piezoelectric effect is pretty straightforward. With certain crystals, if you apply strain, the separation of dipoles in the crystal will set up a piezopotential.

Let’s take that one step further by making contacts on either end of a nanowire made of an appropriate material – in particular, ZnO, but potentially other so-called “wurtzite” semiconductors. Put a potential across is and use mechanical stress in the nanowire to modulate the current: you’ve basically got a FET, with the nanowire acting as a mechanical gate.

Those contacts are Schottky contacts, and the strain allows the Schottky barrier to be raised. But if you shine an appropriate laser on the contact, you can create electron-hole pairs, lowering the Schottky barrier, and even making the contact Ohmic instead.

This three-way interplay between the piezopotential created by strain, the optical excitation, and the transport properties of the semiconductor is referred to as piezophototronics. Say it slowly until you get used to it so you don’t hurt yourself.

How is that useful? Well, for one thing, it can be used, as was just demonstrated at Georgia Tech, to increase the performance of a GaN LED by forming a junction between a GaN film and a ZnO nanowire. The interface formed a p-n junction, with the GaN being the p side and the nanowire being the n side.

By straining the nanowire, they could tune the charge transport and effectively increase the rate of electron-hole recombination, increasing the overall efficiency by 4 times.

That’s the condensed version, the bottom line. You can get more details in their recent release.

Leave a Reply

featured blogs
Jul 3, 2020
[From the last episode: We looked at CNNs for vision as well as other neural networks for other applications.] We'€™re going to take a quick detour into math today. For those of you that have done advanced math, this may be a review, or it might even seem to be talking down...
Jul 2, 2020
Using the bitwise operators in general -- and employing them to perform masking, bit testing, and bit setting/clearing operations in particular -- can be extremely efficacious....
Jul 2, 2020
In June, we continued to upgrade several key pieces of content across the website, including more interactive product explorers on several pages and a homepage refresh. We also made a significant update to our product pages which allows logged-in users to see customer-specifi...

Featured Video

Product Update: Advances in DesignWare Die-to-Die PHY IP

Sponsored by Synopsys

Hear the latest about Synopsys' DesignWare Die-to-Die PHY IP for SerDes-based 112G USR/XSR and parallel-based HBI interfaces. The IP, available in advanced FinFET processes, addresses the power, bandwidth, and latency requirements of high-performance computing SoCs targeting hyperscale data center, AI, and networking applications.

Click here for more information about DesignWare Die-to-Die PHY IP Solutions

Featured Paper

Cryptography: Fundamentals on the Modern Approach

Sponsored by Maxim Integrated

Learn about the fundamental concepts behind modern cryptography, including how symmetric and asymmetric keys work to achieve confidentiality, identification and authentication, integrity, and non-repudiation.

Click here to download the whitepaper

Featured Chalk Talk

Introducing Google Coral

Sponsored by Mouser Electronics and Google

AI inference at the edge is exploding right now. Numerous designs that can’t use cloud processing for AI tasks need high-performance, low-power AI acceleration right in their embedded designs. Wouldn’t it be cool if those designs could have their own little Google TPU? In this episode of Chalk Talk, Amelia Dalton chats with James McKurkin of Google about the Google Coral edge TPU.

More information about Coral System on Module