Electronic Self-passivation of Single Vacancy in Black Phosphorus via a Controlled Ionization
Hanyan Fang, Aurelio Gallardo, Dikshant Dulal, Zhizhan Qiu, Jie Su, Mykola Telychko, Harshitra Mahalingam, Pin Lyu, Yixuan Han, Yi Zheng, Yongqing Cai, Aleksand… 展开作者
Hanyan Fang, Aurelio Gallardo, Dikshant Dulal, Zhizhan Qiu, Jie Su, Mykola Telychko, Harshitra Mahalingam, Pin Lyu, Yixuan Han, Yi Zheng, Yongqing Cai, Aleksandr Rodin, Pavel Jelínek, Jiong Lu
We report that mono-elemental black phosphorus presents a new electronic self-passivation scheme of single vacancy (SV). By means of low-temperature scanning tunneling microscopy and bond-resolved non-contact atomic force microscopy, we demonstrate that the local reconstruction and ionization of SV into negatively charged $\mathrm{SV}^-$ leads to the passivation of dangling bonds and thus the quenching of in-gap states, which can be achieved by mild thermal annealing or STM tip manipulation. SV exhibits a strong and symmetric Friedel oscillation (FO) pattern, while $\mathrm{SV}^-$ shows an asymmetric FO pattern with local perturbation amplitude reduced by one order of magnitude and a faster decay rate. The enhanced passivation by forming $\mathrm{SV}^-$ can be attributed to its weak dipole-like perturbation, consistent with density-functional theory and numerical calculations. Therefore, self-passivated $\mathrm{SV}^-$ is electronically benign and acts as a much weaker scattering center, which may hold the key to further enhance the charge mobility of BP and its analogs.
Effective Passivation of Exfoliated Black Phosphorus Transistors against Ambient Degradation
发现未包封的剥离的黑磷（BP）薄片在暴露于环境条件时发生化学降解。原子力显微镜，静电力显微镜，透射电子显微镜，X-射线光电子能谱学，和傅里叶变换红外光谱表征的结构和化学的降解过程中，表明O2饱和H2O不可逆地与BP反应，形成氧化磷物种。这一解释得到了以下观察结果的进一步支持：与亲水性SiO2相比，疏水性十八烷基三氯硅烷自组装单层和H-Si（111）上的BP降解发生得更快。对于未封装的BP场效应晶体管，环境退化导致在环境中6小时后阈值电压大幅增加，随后在48小时后FET电流开/关比和迁移率降低约10^3。原子层沉积的AlOx覆盖层有效地抑制了环境退化，允许封装的BP FET在环境中保持约10^3的高开/关比和约100 cm 2/（V*s）的迁移率超过两周。这项工作表明，BP的环境降解，可以有效地管理时，薄片充分钝化。反过来，我们提高BP环境稳定性的战略将加速BP在电子和光电应用中的实施。
Synergistic Effects of Phosphorus Doping and Oxygen Vacancies on Formaldehyde Oxidation over CeO$_2$(111): A First Principles Investigation
Université de Lorraine（洛林大学）；CNRS（法国国家科学研究中心）；LEMTA（材料力学与转化实验室）；Université de Monastir（莫纳斯特尔大学）；Faculté des Sciences de Monastir（莫纳斯特尔理学院）；Laboratoire de la matière condensée et nanosciences LR11ES40（凝聚态物质与纳米科学实验室 LR11ES40）；Laboratoire Lorrain de Chimie Moléculaire（洛林分子化学实验室）；Université Lyon 1（里昂第一大学）；IRCELYON（催化、材料和表面研究所）；UMR 5256（联合研究单位 5256）
