Observation of electron distribution by electron microscope
Successful imaging of two-dimensional electron gas by electron holography
Research team observed a much smaller distribution of electrons by observing proteins, nanoparticles, and atoms.
Precise control of the amount of electrons to form at a desired position, and the technology to move it as quickly as possible is a key technology closely related to the performance of semiconductor memory devices and LED optical devices. In order to effectively control the electrons, a high-resolution microscopic observation method that can visually verify and analyze the distribution of the theoretically predicted electrons is needed.
The team developed a method to visually observe the two-dimensional electron gas formed between two kinds of oxides (LaAlO3 / SrTiO3) using 'inline electron holography' which is very sensitive.
- Two-dimensional electron gas refers to a conductive electron bunch formed at the interface of two materials. In the present study, the intrinsic properties of the two - dimensional electron gas were analyzed by correcting all the parameters precisely, although the signal was weak to observe by electron microscope and the influence of several variables was considered.
- Through the developed method, it was observed that the distribution and the density of the two-dimensional electron gas change finely according to the crystal orientation (the angle and the direction in which the atoms are joined). This is a quantum phenomenon that occurs because the energy level of electrons changes according to the observation direction, the researchers explained.
Professor Sang Ho Oh said, "This study was the first to directly observe electron distribution and density changes caused by various quantum phenomena such as ferromagnetic, superconducting, and metal-insulator phase transition. And will play an important role in connecting quantum phenomena to device research, "explains the study's significance.
This research was supported by the Ministry of Science and Technology, Ministry of Information and Communication, the Korea Research Foundation Future Material Discovery Project, Basic Research Project (Advanced Research), and the US Air Force Asia Office (AOARD). Published in the March issue of Nature Nanotechnology *, an international journal in nanotechnology. In addition, a follow-up study was carried out with a team of Professor Um, Chang-Bum of the University of Wisconsin-Madison (USA), and the two-dimensional hall gas was successfully separated from the two-dimensional electron gas and the result was shown in the March issue of Nature Materials Published on July 7).
* Nature Nanotechnology: The most authoritative international journal published by Nature in the field of nanotechnology. It was launched in 2010 and the impact factor is 38.986