This year marks the 25th and 20th anniversaries of the scanning tunneling and atomic force microscopes (STM and AFM), respectively. Their development allowed the world of atoms and molecules to be visualized for the first time. Today, thanks to these instruments, we are able to appreciate a whole new reality in which molecules can be individually addressed, patterned, and assembled into structures, and all manner of properties probed on the nanoscale. These techniques have also increased access to the atomic world as the microscopes have become more established, easier to use, and, most importantly, cheaper. It is no accident that the interest in all things nano has grown with the development of these techniques.
These landmarks were celebrated at the International Conference on Nanoscience and Technology last month, which showcased the latest developments in scanning probe microscopies (SPM) and the best interdisciplinary nanoscience they have enabled. It was appropriate that the conference was held in Basel, Switzerland near where Gerd Binnig and Heinrich Rohrer first developed the STM at IBM's Zürich Research Laboratory.
The conference started with talks by both Binnig and Rohrer, and I have never felt such a palpable sense of excitement. But it was Christoph Gerber, one of the inventors of the AFM, who gave voice to that feeling. Before introducing the two Nobel laureates, he recounted the passion, perseverance, and fun of developing the STM and showed some of the first images that were obtained. “Getting up close and personal with atoms for the first time really sent shivers down the spine,” said Gerber.
Binnig was hired by Rohrer to IBM in 1978 and they began to talk about what projects he could work on. “We wanted to be able to investigate surfaces locally, and looked at various existing techniques that might be able to do that,” Binnig told me. But it quickly became clear there was nothing, and that they would have to invent something instead. “Once you have a probe to conduct local investigations, in principle, it is the next step to scan the probe to build up an image. So there was not one single event [that led to the development of the STM], it was a journey,” he said. However, it must have been a relatively quick journey. Rohrer and Binnig realized their idea within just a few years and published the seminal Applied Physics Letters paper in 1981.
While the technique has reached its quarter century, the conference made it clear that there is still plenty that can be achieved. The conference covered efforts to achieve video-rate imaging, new force-sensing techniques, and the use of vast tip arrays; while applications span everything from localized chemical reactions to pulling apart biomolecules. It is clear that SPM is in the prime of life.