Goodbye silicon, hello organic molecules

Vital research, because scientists predict that in 20 years the average transistor dimension will be around 5 nanometers, or 10,000 times smaller than the width of a human hair.

Few people have probably ever associated a single organic molecule with an everyday transistor chip. But too keep pace with the transistor chip’s constant rate of miniaturization, silicon could one day cease to be the chip-industry standard, replaced by single organic molecules, such as those found in everyday chemicals.

As unlikely as this may seem, single molecule devices promise to be the new radical generation of electronic devices. And that is why recent Veni-grant winner Dr. Kevin O’Neill is now spearheading a research project on single-molecule light emitting devices: O’Neill believes information gained from the tests could result in the ability to synthesize single organic molecules into active parts of transistors, which in turn will be used in computers, mobile phones and other electronic devices.

Born and raised in Ireland, O’Neill studied in England, before pursuing his PhD degree at Cornell University (US). During his PhD at Cornell, O’Neill collaborated on a project with Herre van der Zant, the current head of of TU Delft’s Molecular Electronics and Devices (MED) department. Van der Zant then invited O’Neill to work for a few months in TU Delft.

Van der Zant encouraged O’Neill to submit a research proposal for a Marie Curie fellowship. “I was sidetracked,” O’Neill recalls. “It was very interesting work and kept me curious enough to stay on and look for other projects.” A few months turned into a couple years, and O’Neill has now been living in the Netherlands for almost three years. He and his wife are expecting their first child in January 2007.

Having been used to living in the States, O’Neill found everything in Holland strangely “compacted”, but he enjoys living here. “Students in the U.S. and Holland are surprisingly similar,” he says. “It’s very informal here, and TU Delft students also have their own special kind of pride, which is quite fun and gives me lots of energy. I like how students here don’t mind trying out half-developed ideas to see how they work out. They don’t have to write up complete proposals before testing their ideas. It’s a very fresh approach.”
Electroluminescence

About 18 months ago, O’Neill started working on electrical transport through single-molecules. “Given the constant rate of miniaturization of integrated circuits, we’ll require the size of a transistor to be a molecule.” Indeed, scientists predict that in 20 years the average transistor dimension will be around 5 nanometers, or 10,000 times smaller than the width of a human hair. Too small for silicon to continue being the chip-industry standard. Thus, research in the Molecular Electronics and Devices (MED) is focusing on studying organic molecules measuring around 5 nanometers as the “building blocks” for electronic devices, in which the resistance can be tuned like a conventional transistor.

For those who are used to traditional electronic designs, this new approach takes getting used to. Whereas the material properties of silicon are catered to specific requirements of a device, single organic molecules must have desired properties when they’re synthesized. And this process happens before they’re incorporated into the device. Synthesis therefore tailors the molecule to a specific purpose.

O’Neill’s research project also sets out to discover the crucial difference between conventional electronics and single organic molecule devices. While researchers roughly understand how it works when metal leads are connected to the device, they still need detailed information about how much influence on the device the molecule has when it has an electrical connection. Until recently, devices have been studied by monitoring their conductive properties. This research aims to obtain more information by measuring the emitted light.

“It’s very difficult to determine if you have a single molecule trapped between your electrodes just by looking at what we call the transport characteristics,” O’Neill explains. “What this project proposes is that we don’t have to look at the current. We can also look at the light that comes out of your electrical device.”

O’Neill believes that the so-called electroluminescence (how the light and spectrum depends on the electric current) gives important information about what the molecule is doing and how it’s interacting with the metal leads that provide electrical connection.
Barriers

An interesting off-shoot of O’Neill’s research stems from the fact that a single molecule forms the heart of this electronic design. Since a single molecule emits a single photon at a time, at a rate determined by the current, this source of light is also a promising new route towards on-demand single photon generation. Such a technology is of great interest to the many scientists seeking to build a computer that takes advantage of quantum effects to perform calculations.

O’Neill submitted his research proposal for a Veni-grant to the Netherlands Organization for Scientific Research (NOW), which gives grants to promising young scientists who just graduated with PhDs, allowing them to continue researching and developing new ideas for the following three years.

For this research project, Van der Zant is the group leader. Along with PhD student Edgar Osorio and O’Neill, the trio forms the core research group. In addition, they will work with other MSc students and theorists from Germany and the Netherlands. And because there are many more organic molecules to choose from than conventional semi-conducting materials, organic chemists from Italy and Denmark will help them select the molecules that are good candidates for their devices.

So when does O’Neill expect the technology to mature into a working single-molecule transistor? “This will be approximately a 10-year project,” O’Neill predicts, adding that there’s still a lot of additional research to be done. “Understanding the effects of the metal contacts, interlinking single molecules to make up an electronic circuit, understanding how electronic structure affects device performance, are all barriers that need to be overcome in order to achieve this goal. If Moore’s law is correct, we would need at least 20 years to do this!”

Dr. Kevin O’Neill. (Photo: Sam Rentmeester/FMAX)

Few people have probably ever associated a single organic molecule with an everyday transistor chip. But too keep pace with the transistor chip’s constant rate of miniaturization, silicon could one day cease to be the chip-industry standard, replaced by single organic molecules, such as those found in everyday chemicals.

As unlikely as this may seem, single molecule devices promise to be the new radical generation of electronic devices. And that is why recent Veni-grant winner Dr. Kevin O’Neill is now spearheading a research project on single-molecule light emitting devices: O’Neill believes information gained from the tests could result in the ability to synthesize single organic molecules into active parts of transistors, which in turn will be used in computers, mobile phones and other electronic devices.

Born and raised in Ireland, O’Neill studied in England, before pursuing his PhD degree at Cornell University (US). During his PhD at Cornell, O’Neill collaborated on a project with Herre van der Zant, the current head of of TU Delft’s Molecular Electronics and Devices (MED) department. Van der Zant then invited O’Neill to work for a few months in TU Delft.

Van der Zant encouraged O’Neill to submit a research proposal for a Marie Curie fellowship. “I was sidetracked,” O’Neill recalls. “It was very interesting work and kept me curious enough to stay on and look for other projects.” A few months turned into a couple years, and O’Neill has now been living in the Netherlands for almost three years. He and his wife are expecting their first child in January 2007.

Having been used to living in the States, O’Neill found everything in Holland strangely “compacted”, but he enjoys living here. “Students in the U.S. and Holland are surprisingly similar,” he says. “It’s very informal here, and TU Delft students also have their own special kind of pride, which is quite fun and gives me lots of energy. I like how students here don’t mind trying out half-developed ideas to see how they work out. They don’t have to write up complete proposals before testing their ideas. It’s a very fresh approach.”
Electroluminescence

About 18 months ago, O’Neill started working on electrical transport through single-molecules. “Given the constant rate of miniaturization of integrated circuits, we’ll require the size of a transistor to be a molecule.” Indeed, scientists predict that in 20 years the average transistor dimension will be around 5 nanometers, or 10,000 times smaller than the width of a human hair. Too small for silicon to continue being the chip-industry standard. Thus, research in the Molecular Electronics and Devices (MED) is focusing on studying organic molecules measuring around 5 nanometers as the “building blocks” for electronic devices, in which the resistance can be tuned like a conventional transistor.

For those who are used to traditional electronic designs, this new approach takes getting used to. Whereas the material properties of silicon are catered to specific requirements of a device, single organic molecules must have desired properties when they’re synthesized. And this process happens before they’re incorporated into the device. Synthesis therefore tailors the molecule to a specific purpose.

O’Neill’s research project also sets out to discover the crucial difference between conventional electronics and single organic molecule devices. While researchers roughly understand how it works when metal leads are connected to the device, they still need detailed information about how much influence on the device the molecule has when it has an electrical connection. Until recently, devices have been studied by monitoring their conductive properties. This research aims to obtain more information by measuring the emitted light.

“It’s very difficult to determine if you have a single molecule trapped between your electrodes just by looking at what we call the transport characteristics,” O’Neill explains. “What this project proposes is that we don’t have to look at the current. We can also look at the light that comes out of your electrical device.”

O’Neill believes that the so-called electroluminescence (how the light and spectrum depends on the electric current) gives important information about what the molecule is doing and how it’s interacting with the metal leads that provide electrical connection.
Barriers

An interesting off-shoot of O’Neill’s research stems from the fact that a single molecule forms the heart of this electronic design. Since a single molecule emits a single photon at a time, at a rate determined by the current, this source of light is also a promising new route towards on-demand single photon generation. Such a technology is of great interest to the many scientists seeking to build a computer that takes advantage of quantum effects to perform calculations.

O’Neill submitted his research proposal for a Veni-grant to the Netherlands Organization for Scientific Research (NOW), which gives grants to promising young scientists who just graduated with PhDs, allowing them to continue researching and developing new ideas for the following three years.

For this research project, Van der Zant is the group leader. Along with PhD student Edgar Osorio and O’Neill, the trio forms the core research group. In addition, they will work with other MSc students and theorists from Germany and the Netherlands. And because there are many more organic molecules to choose from than conventional semi-conducting materials, organic chemists from Italy and Denmark will help them select the molecules that are good candidates for their devices.

So when does O’Neill expect the technology to mature into a working single-molecule transistor? “This will be approximately a 10-year project,” O’Neill predicts, adding that there’s still a lot of additional research to be done. “Understanding the effects of the metal contacts, interlinking single molecules to make up an electronic circuit, understanding how electronic structure affects device performance, are all barriers that need to be overcome in order to achieve this goal. If Moore’s law is correct, we would need at least 20 years to do this!”

Dr. Kevin O’Neill. (Photo: Sam Rentmeester/FMAX)