洞察CdTe/CdS核心/外量子点中对波段对齐转移,载体定位和再组合动力学的影响
Lihong Jing1, Stephen V Kershaw, Tobias Kipp
1Institute of Chemistry, Chinese Academy of Sciences , Bei Yi Jie 2, Zhong Guan Cun, Beijing 100190, China.
Journal of the American Chemical Society
|January 17, 2015
概括
应变显著影响半导体量子点的光学特性. 这项研究修改了有效质量近似模型,以显示CdTe/CdS核心/外量子点中的应变如何改变电子结构和重组动力学.
科学领域:
- 材料科学 材料科学 材料科学
- 纳米技术纳米技术
- 固态物理 固态物理
背景情况:
- 半导体量子点 (QD) 具有尺寸依赖的光学特性.
- 核心/外QD中的压力,如CdTe/CdS,源于格子不匹配,影响它们的行为.
- 详细调查应变对 QD 光学特性的影响至关重要.
研究的目的:
- 调查CdTe/CdS核心/外量子点在光学特性上的应变诱导效应.
- 修改理论模型以准确预测这些与菌株相关的现象.
- 了解应变如何影响电子结构,载体定位和重组动力学.
主要方法:
- 合成各种核心尺寸和外厚度的水性CdTe/CdS核心/外QD.
- 使用稳定状态吸收,光和瞬态光光谱学的表征.
- 修改有效质量近似 (EMA) 模型,将带变形电位理论纳入其中,以考虑应变.
主要成果:
- 监测了的生长,并计算了应变诱导的带对齐转移.
- 经过修改的EMA模型成功模拟了电子结构,载体定位和电子孔波函数重叠.
- 压力被证明通过影响波函数空间分布来改变电子孔重组动力学.
结论:
- 应变通过修改其电子结构,显著影响了核心/外QD不匹配的光学特性.
- 菌株修改的EMA模型提供了准确的预测,验证了菌株效应的重要性.
- 这项工作为量身定制的光学应用提供了对量子点的应变工程的更深入的理解.
相关概念视频
Carrier Generation and Recombination
1.6K
Carrier generation is the process by which electron-hole pairs (EHPs) are created within the semiconductor. In direct-bandgap semiconductors, such as gallium arsenide (GaAs), this occurs efficiently when energy absorption prompts valence electrons to leap into the conduction band, leaving behind holes.
This process is given by the generation rate G and is efficient due to the conservation of momentum between the valence band maximum and conduction band minimum.
Indirect generation involves an...
This process is given by the generation rate G and is efficient due to the conservation of momentum between the valence band maximum and conduction band minimum.
Indirect generation involves an...
1.6K
Energy Bands in Solids
2.6K
Isolated atoms have discrete energy levels that are well described by the Bohr model. And, it quantifies the energy of an electron in a hydrogen atom as En. Higher quantum numbers 'n' yield less negative, closer electron energy levels.
Band Formation:
When atoms are brought close together, as in a solid, these discrete energy levels begin to split due to the overlap of electron orbitals from adjacent atoms. This split occurs because of the Pauli exclusion principle, which states...
Band Formation:
When atoms are brought close together, as in a solid, these discrete energy levels begin to split due to the overlap of electron orbitals from adjacent atoms. This split occurs because of the Pauli exclusion principle, which states...
2.6K
π Electron Effects on Chemical Shift: Overview
1.9K
An applied magnetic field causes loosely bound π-electrons in organic molecules to circulate, producing a local or induced diamagnetic field over a large spatial volume. As the molecules tumble in solution, the field generated by π-electrons in spherical substituents results in a zero net field. However, the net field generated by π-electrons in non-spherical substituents is not zero. The effect of this induced field depends on the orientation of the molecule with respect to B0,...
1.9K
π Electron Effects on Chemical Shift: Aromatic and Antiaromatic Compounds
2.1K
In aromatic compounds, such as benzene, the circulation of (4n + 2) π-electrons sets up a diamagnetic or diatropic ring current around the perimeter of the molecule. This current induces a magnetic field that opposes the external field inside the ring and reinforces it on the outside. The protons in benzene are deshielded and exhibit high chemical shifts in the range 6.5–8.5 ppm. The shielding effect at the center of the ring is evident in complex aromatic molecules, such as...
2.1K
Biasing of Metal-Semiconductor Junctions
866
Biasing metal-semiconductor junctions involves applying a voltage across the junction. Specifically, the metal is connected to a voltage source, while the semiconductor is grounded. This technique is essential for controlling the direction and magnitude of current flow in electronic devices, including diodes, transistors, and photovoltaic cells.
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
In Schottky junctions, where the semiconductor is n-type, applying a positive voltage to the metal relative to the semiconductor reduces its Fermi...
866
¹H NMR: Interpreting Distorted and Overlapping Signals
1.8K
Spin systems where the difference in chemical shifts of the coupled nuclei is greater than ten times J are called first-order spin systems. These nuclei are weakly coupled, and their chemical shifts and coupling constant can generally be estimated from the well-separated signals in the spectrum.
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are...
1.8K


