Li Penghui, Dong Linpeng, Li Chong, Lu Bin, Yang Chen, Peng Bo, Wang Wei, Miao Yuanhao, Liu Weiguo
Shaanxi Province Key Laboratory of Thin Films Technology and Optical Test, Xi'an Technological University, Xi'an, 710032, China.
Research and Development Center of Optoelectronic Hybrid IC, Guangdong Greater Bay Area Institute of Integrated Circuit and System, Guangdong, 510535, China.
Nanoscale. 2023 Jul 20;15(28):12105-12115. doi: 10.1039/d3nr00899a.
Monolayer (ML) GaO with outstanding properties is promising for advanced nanodevice applications; however, its high exfoliation energy makes obtaining it challenging. In this study, we propose a more efficient solution to obtain ML GaO by exfoliation from indium-doped bulk β-GaO. The exfoliation efficiency with the assistance of In-doping and the doping influence on the stability and structural and electronic properties of ML GaO are systematically studied using first-principles calculations. The exfoliation energy of ML GaO is found to be reduced by 28% and is of the same order of magnitude as that of typical van der Waals (vdWs) 2D materials. Besides, excellent stability is preserved for ML GaO at extremely high In doping concentration by phonon spectrum and molecular dynamics inspections. The bandgap of ML GaO decreases from 4.88 to 4.25 eV with increased In concentration, and the modification of the VBM converts ML GaO to a direct bandgap semiconductor. With the suppression of ZA mode phonon scattering, the pristine and In-doped ML GaO exhibit high electron mobility, whereas the strong electron-phonon coupling (EPC) effect significantly decreases the hole mobility. Finally, the transfer characteristics of 5 nm MOSFETs based on the pristine and In-doped ML GaO with varied In concentrations are simulated based on the non-equilibrium Green's function (NEGF) formalism. The for HP has a maximum of 3060 μA μm at In doping concentration of 5% and is triple that of the pristine ML GaO for LP at In doping concentration of 20%. The FOMs of n-type MOSFETs based on the In-doped ML GaO and typical 2D materials are compared and shows huge potential for sub-5 nm applications. Our study applies a new strategy for obtaining ML GaO and can also improve the device performance at the same time.
具有优异性能的单层（ML）GaO在先进纳米器件应用中具有广阔前景；然而，其高剥离能使得获取它具有挑战性。在本研究中，我们提出了一种更有效的解决方案，即通过从铟掺杂的块状β - GaO中剥离来获得ML GaO。利用第一性原理计算系统地研究了铟掺杂辅助下的剥离效率以及掺杂对ML GaO稳定性、结构和电子性质的影响。发现ML GaO的剥离能降低了28%，与典型的范德华（vdWs）二维材料处于同一数量级。此外，通过声子谱和分子动力学研究表明，在极高铟掺杂浓度下，ML GaO仍保持优异的稳定性。随着铟浓度的增加，ML GaO的带隙从4.88 eV减小到4.25 eV，价带顶的变化使ML GaO转变为直接带隙半导体。随着ZA模式声子散射的抑制，原始和铟掺杂的ML GaO表现出高电子迁移率，而强电子 - 声子耦合（EPC）效应显著降低了空穴迁移率。最后，基于非平衡格林函数（NEGF）形式，模拟了基于不同铟浓度的原始和铟掺杂ML GaO的5 nm MOSFET的传输特性。对于高功耗（HP），在铟掺杂浓度为5%时，最大电流为3060 μA/μm，是原始ML GaO在铟掺杂浓度为20%时低功耗（LP）电流的三倍。比较了基于铟掺杂ML GaO的n型MOSFET与典型二维材料的优值因子（FOMs），显示出在5 nm以下应用中的巨大潜力。我们的研究为获取ML GaO应用了一种新策略，同时还能提高器件性能。
