Department of Physics, Beijing Normal University, Beijing, 100875, China.
Sci Rep. 2018 Jan 10;8(1):404. doi: 10.1038/s41598-017-18746-4.
Experimentally, we found the percentage of low valence cations, the ionization energy of cations in film, and the band gap of substrates to be decisive for the formation of two-dimensional electron gas at the interface of amorphous/crystalline oxide (a-2DEG). Considering these findings, we inferred that the charge transfer from the film to the interface should be the main mechanism of a-2DEG formation. This charge transfer is induced by oxygen defects in film and can be eliminated by the electron-absorbing process of cations in the film. Based on this, we propose a simple dipole model that successfully explains the origin of a-2DEG, our experimental findings, and some important properties of a-2DEG.
实验中，我们发现低价阳离子的比例、薄膜中阳离子的电离能以及衬底的能带隙对于非晶/晶态氧化物(a-2DEG)界面处二维电子气的形成至关重要。考虑到这些发现，我们推断薄膜向界面的电荷转移应该是 a-2DEG 形成的主要机制。这种电荷转移是由薄膜中的氧缺陷引起的，可以通过薄膜中阳离子的电子吸收过程来消除。基于这一点，我们提出了一个简单的偶极子模型，成功地解释了 a-2DEG 的起源、我们的实验发现以及 a-2DEG 的一些重要性质。
