We present a theoretical model of composite excitonic states in doped semiconductors. Many-body interactions between a photoexcited electron-hole pair and the electron gas are integrated into a computationally tractable few-body problem, solved by the variational method. We focus on electron-doped ML-MoSe$_2$ and ML-WSe$_2$ due to the contrasting character of their conduction bands. In both cases, the core of the composite is a tightly-bound trion (two electrons and valence-band hole), surrounded by a region depleted of electrons. The composite in ML-WSe$_2$ further includes a satellite electron with different quantum numbers. The theory is general and can be applied to semiconductors with various energy-band properties, allowing one to calculate their excitonic states and to quantify the interaction with the Fermi sea.
Relaxation and darkening of excitonic complexes in electrostatically-doped monolayer semiconductors: Roles of exciton-electron and trion-electron interactions
Exciton dynamics and high-temperature excitonic superfluidity in S-doped graphyne
São Paulo State University (UNESP)(圣保罗州立大学);University of Brasília(巴西利亚大学);University of Rome Tor Vergata(罗马第二大学);Universidad Privada del Norte(北方私立大学)
Tuning near-gap electronic structure, interface charge transfer and visible light response of hybrid doped graphene and Ag3PO4 composite: Dopant effects
掺杂石墨烯(GR)/半导体纳米复合材料的增强的光催化性能最近被广泛观察到,但对其背后的潜在机制的理解仍然遥不可及。作为研究掺杂效应的模型体系,我们采用第一性原理计算研究了掺杂GR/Ag 3 PO 4纳米复合材料的电子结构和光学性质,结果表明掺杂剂可以调节GR/Ag 3 PO 4(100)复合材料的带隙、近带隙电子结构和界面电荷转移.有趣的是,掺杂原子和键合到掺杂剂上的C原子由于相互作用引起的电荷重新分布而带正电荷或负电荷,因此成为掺杂剂的活性位点。掺杂可以增强可见光吸收和光生电子转移。我们认为,N原子可能是GR/Ag 3 PO 4光催化剂的最佳掺杂。该工作可以合理化现有的实验结果,N掺杂GR-半导体复合材料,并丰富了我们的理解掺杂GR基复合材料中的掺杂剂的作用,开发高性能的光催化剂。
Interfacial Synergy in Ag-Doped CuO-AgCl-g-C3N4 Composites for Efficient Charge Separation and Low-power Methylene Blue Degradation
Indian Institute of Technology Indore(印度印多尔理工学院);Heriot-Watt University(赫瑞-瓦特大学);Ariel University(阿里埃勒大学);King Fahd University of Petroleum and Minerals(法赫德国王石油与矿物大学)
Nitrogen doped In$_2$O$_3$-ZnO nanocomposite thin film based sensitive and selective ethanol sensor
纳米复合金属氧化物薄膜在气体传感器领域中表现出可靠的品质,因为异质界面形成提供了集体机会。本文以尿素为氮源,采用湿化学法制备了氮掺杂介孔In $_2$ O $_3$ -ZnO纳米复合薄膜。SEM研究表明,复合薄膜中形成了介孔纳米复合薄膜,其表面孔分布的均匀性取决于In $_2$ O $_3$和ZnO在复合薄膜中的相对比例。HRTEM研究表明,在纳米复合薄膜中,N-In $_2$ O $_3$和N-ZnO晶粒之间形成了尖锐的界面。纳米复合薄膜的乙醇传感性能进行了测试,在广泛的范围内的温度,乙醇蒸汽浓度和相对湿度。具有等比例的In $_2$ O $_3$和ZnO的氮掺杂纳米复合物薄膜在合理的操作温度下表现出优异的乙醇感测性能(对于50 ppm的乙醇,在200 °C下约94%)、快速的响应时间(约两秒)、随时间的稳定性、增强的对湿度的弹性和对乙醇的选择性超过各种其他挥发性有机化合物。
Bandgap renormalization of modulation doped quantum wires
我们测量了调制掺杂的T形量子线阵列的光致发光谱,它是用表面门调制的一维密度n_e的函数。我们提出了自洽的电子结构计算这种设备,它显示了带隙重整化,当校正激子能量和屏蔽,在很大程度上是不敏感的n_e,这是在定量极好的协议与数据。计算(cf。cond-mat/9908349)示出了包括屏蔽电子和与空穴结合的电子之间的正交性的重要性。计算表明,电子和空穴在3 x 10^6 cm^-1的范围内仍然保持束缚状态,因此激子的稳定性远远超过保守的莫特判据。
Observation of quasi-steady dark excitons and gap phase in a doped semiconductor
Institute for Advanced Studies, Wuhan University(武汉大学高等研究院);Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences(中国科学院物理研究所);School of Physical Sciences, University of Chinese Academy of Sciences(中国科学院大学物理科学学院);School of Physics and Technology, Wuhan University(武汉大学物理科学与技术学院);Songshan Lake Materials Laboratory(松山湖材料实验室);Wuhan Institute of Quantum Technology(武汉量子技术研究院)