Erasable and recreatable two-dimensional electron gas at the heterointerface of SrTiO<sub>3</sub> and a water-dissolvable overlayer.

Han, Kun; Hu, Kaige; Li, Xiao; Huang, Ke; Huang, Zhen; Zeng, Shengwei; Qi, Dongchen; Ye, Chen et al. · Sci Adv · 2019

basic_science · Level V

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Abstract

While benefiting greatly from electronics, our society also faces a major problem of electronic waste, which has already caused environmental pollution and adverse human health effects. Therefore, recyclability becomes a must-have feature in future electronics. Here, we demonstrate an erasable and recreatable two-dimensional electron gas (2DEG), which can be easily created and patterned by depositing a water-dissolvable overlayer of amorphous Sr<sub>3</sub>Al<sub>2</sub>O<sub>6</sub> (<i>a</i>-SAO) on SrTiO<sub>3</sub> (STO) at room temperature. The 2DEG can be repeatedly erased or recreated by depositing the <i>a</i>-SAO or dissolving in water, respectively. Photoluminescence results show that the 2DEG arises from the <i>a</i>-SAO-induced oxygen vacancy. Furthermore, by gradually depleting the 2DEG, a transition of nonlinear to linear Hall effect is observed, demonstrating an unexpected interfacial band structure. The convenience and repeatability in the creation of the water-dissolvable 2DEG with rich physics could potentially contribute to the exploration of next generation electronics, such as environment-friendly or water-soluble electronics.