Silicon-based transistors are approaching their physical limits and thus new high-mobility semiconductors are sought to replace silicon in the microelectronics industry. Both bulk materials (such as silicon-germanium and III–V semiconductors) and low-dimensional nanomaterials (such as one-dimensional carbon nanotubes and two-dimensional transition metal dichalcogenides) have been explored, but, unlike silicon, which uses silicon dioxide (SiO₂) as its gate dielectric, these materials suffer from the absence of a high-quality native oxide as a dielectric counterpart. This can lead to compatibility problems in practical devices. Here, we show that an atomically thin gate dielectric of bismuth selenite (Bi₂SeO₅) can be conformally formed via layer-by-layer oxidization of an underlying high-mobility two-dimensional semiconductor, Bi₂O₂Se. Using this native oxide dielectric, high-performance Bi₂O₂Se field-effect transistors can be created, as well as inverter circuits that exhibit a large voltage gain (as high as 150). The high dielectric constant (~21) of Bi₂SeO₅ allows its equivalent oxide thickness to be reduced to 0.9 nm while maintaining a gate leakage lower than thermal SiO₂. The Bi₂SeO₅ can also be selectively etched away by a wet chemical method that leaves the mobility of the underlying Bi₂O₂Se semiconductor almost unchanged.

硅基晶体管正接近其物理极限，因此在微电子工业中，正在寻求新的高迁移率半导体来替代硅。既探索了块状材料（例如硅锗和III-V半导体），又研究了低维纳米材料（例如一维碳纳米管和二维过渡金属二硫化碳），但与硅不同的是，硅使用二氧化硅（ SiO ₂）作为其栅极电介质，这些材料缺少作为电介质对应物的高质量天然氧化物。这可能导致在实际设备中的兼容性问题。在这里，我们表明，铋硒的原子级薄的栅极电介质的（Bi ₂的SeO ₅可以通过下面的高迁移率二维半导体Bi ₂ O ₂ Se的逐层氧化共形形成。使用这种天然氧化物电介质，可以创建高性能的Bi ₂ O ₂ Se场效应晶体管，以及具有大电压增益（高达150）的逆变器电路。Bi ₂ SeO ₅的高介电常数（〜21 ）使其等效氧化物厚度减小到0.9 nm，同时保持低于热SiO ₂的栅极泄漏。还可以通过湿化学方法选择性地蚀刻掉Bi ₂ SeO ₅，从而留下下面的Bi ₂的迁移率O ₂ Se半导体几乎不变。