二维硒化镓与铁电异质结的构筑及其电输运性能研究

Two-dimensional (2D) gallium selenide (GaSe) has attracted much attention due to its amazing nonlinear optical properties and suitable electronic structure. However, the field effect mobility of 2D GaSe is low, restricting its practical applications in electronic and optoelectronic devices. In this proposed project, we will fabricate the heterostructure of ferroelectric and 2D GaSe in order to improve the transport properties of 2D GaSe by ferroelectric gating. Firstly, the heterostructure of 2D GaSe and different ferroelectric materials will be fabricated by transferring 2D GaSe to or directly growing on the target ferroelectric materials. The growth mechanism of chemical vapor deposition will be investigated. Secondly, the effects of ferroelectric non-volatility and nonlinear polarization on the transport properties of 2D GaSe will be systematically studied to access a higher mobility of 2D GaSe. A non-volatile memory will be constructed based on a field effect transistor (FET) structure by using ferroelectric as gate dielectric and 2D GaSe as channel semiconductor. Furthermore, it will be interesting to investigate the external optical and thermal effects on the transport properties of the fabricated FETs. Thirdly, the coupling between ferroelectric and 2D materials will be explored, and the underlying mechanism will be explained. More importantly, the ferroelectric gating effects will be systematically summarized in the FET structure. Besides, first-principles method calculations will be employed for further understanding. In view of applications, this provides us theoretical evidence and technical support to access the improved transport properties of 2D GaSe for potential applications in future nano-electronic and optoelectronic devices.

二维硒化镓（GaSe）不仅保留了其块状晶体中优良的非线性光学特性，还具有合适的电子结构，引起了国内外广泛关注。但二维GaSe场效应迁移率较低，制约了它在光电器件中的实际应用。本项拟以二维GaSe与铁电异质结的构筑及其电输运性能的改善为目标开展研究工作，主要包括：1）实现二维GaSe的可控生长，研究其生长机理，采用不同的铁电材料，借助转移法和直接生长法构筑GaSe/铁电异质结；2）研究铁电极化的非线性、非易失性等对GaSe电输运的调控，改善二维GaSe载流子迁移率，并在此基础上构建GaSe/铁电场效应管器件，研究器件的非易失性存储，以对外界光、温度的响应；3）结合第一性原理计算，研究铁电对GaSe电输运的调控规律和调控机制，以及铁电在GaSe为沟道材料的场效应管器件中的作用，阐明界面调控的微观机制。研究成果可以为改善二维GaSe电输运性能提供方法和理论支持。

硒化镓（GaSe）晶体作为一种优良的红外非线性光学材料已经被广泛研究。其透光波段宽，在0.62-20 μm 范围内没有明显的吸收，因此不会出现中红外波段透光率下降的问题。同时GaSe 晶体可以实现中红外、远红外、甚至太赫兹波段的激光频率转换。二维GaSe不仅保留了其块状晶体中优良的非线性光学特性，还具有合适的电子结构，引起了国内外广泛关注。但二维GaSe场效应迁移率较低，制约了它在光电器件中的实际应用。本项以二维GaSe与铁电异质结的构筑及其电输运性能的改善为目标开展研究工作，主要研究包括：1）实现二维GaSe的可控生长，研究其生长机理，采用不同的铁电材料，借助转移法和直接生长法构筑GaSe/铁电异质结；2）研究铁电极化的非线性、非易失性等对GaSe电输运的调控，改善二维GaSe载流子迁移率，在铁电栅极调控下，GaSe场效应载流子迁移率由机械剥离法制备转移至SiO2衬底上的0.5 cm2V-1s-1，提高至转移至PMN-PT衬底上的16 cm2V-1s-1，并进一步通过脉冲激光沉积方法直接生长在PMN-PT衬底上提高至18 cm2V-1s-1；3）并在此基础上构建GaSe/铁电场效应管器件，研究器件的非易失性存储，以及铁电在GaSe为沟道材料的场效应管器件中的作用，阐明界面调控的微观机制。研究成果可以为改善二维GaSe电输运性能提供方法和理论支持。