Band edge smearing due to compositional disorder in multi-componentd-dimensional alloys

The band alignment of Mg(OH)2-based heterostructures is investigated based on first-principles calculation. (111)-MgO/(0001)-Mg(OH)2 and (0001)-wurtzite ZnO/(0001)-Mg(OH)2 heterostructures are considered. The O 2s level energy is obtained for each O atom in the heterostructure supercell, and the band edge energies are evaluated following the procedure of the core-level spectroscopy. The calculation is based on the generalized gradient approximation with the on-site Coulomb interaction parameter U considered for Zn. For MgO/Mg(OH)2, the band alignment is of type II, and the valence band edge of MgO is higher by 1.6 eV than that of Mg(OH)2. For ZnO/Mg(OH)2, the band alignment is of type I, and the valence band edge of ZnO is higher by 0.5 eV than that of Mg(OH)2. Assuming the transitivity rule, it is expected that Mg(OH)2 can be used for certain types of heterostructure solar cells and dye-sensitized solar cells to improve the performance.

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Selectivity and in-band impedance enhancement of a compact slot antenna with defected ground structures

International Journal of Microwave and Wireless Technologies ◽

10.1017/s1759078719000734 ◽

2019 ◽

Vol 11 (10) ◽

pp. 1010-1016

Author(s):

Hailong Yang ◽

Xiaoli Xi ◽

Lili Wang ◽

Yuchen Zhao ◽

Xiaomin Shi

Keyword(s):

Reflection Coefficient ◽

Impedance Matching ◽

Ultra Wideband ◽

Band Edge ◽

Slot Antenna ◽

Defected Ground Structure ◽

Pass Filter ◽

Low Pass Filter ◽

Uwb Antennas ◽

Low Pass

AbstractIn this study, a new ultra-wideband (UWB) band-edge selectivity antenna with a modified radiation slot using defected ground structure (DGS) is presented to obtain bandpass filtering reflection coefficient and gain performance. The well-designed DGS is designed on backside metallic of the substrate and can be seen as a low-pass filter that provides a good roll-off at a higher frequency. By connecting the DGS and the stepped slot and making them merge with each other, good cut-off property in the upper passband and better in-band impedance characteristics are obtained. Measured results show that the proposed design not only shows good band-edge selectivity in reflection coefficient and gain performance but also has a good impedance matching of −13.5 dB reflection coefficients and a good radiation efficiency of 90% in the operating frequencies. The measured bandwidth defined with the reflection coefficient less than −10 dB is from 3.1–11.2 GHz. Furthermore, the size of the filtering UWB antenna is 22 mm × 12 mm, which is smaller than many individual UWB antennas and UWB filters.

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Ultrathin wideband slot and patch FSS elements with sharp band edge characteristics

International Journal of Electronics ◽

10.1080/00207217.2020.1726493 ◽

2020 ◽

Vol 107 (9) ◽

pp. 1365-1385

Author(s):

V. Krushna Kanth ◽

S. Raghavan

Keyword(s):

Band Edge ◽

Sharp Band

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Prolonging the lifetime of excited electrons of QDs by capping them with π-conjugated thiol ligands

Journal of Materials Chemistry C ◽

10.1039/c3tc32523g ◽

2014 ◽

Vol 2 (16) ◽

pp. 2939-2943 ◽

Cited By ~ 9

Author(s):

Jie Chang ◽

Hongbo Xia ◽

Suli Wu ◽

Shufen Zhang

Keyword(s):

Energy Levels ◽

Excited Electron ◽

Band Edge ◽

Lumo Energy ◽

Stable Environment ◽

Cdte Qds ◽

Thiol Ligands ◽

New Strategy

A new strategy is reported here to stabilize the excited electrons within QDs using-conjugated ligand. An electron delocalized field is formed by mixing the LUMO energy levels of π-conjugated ligand with conductive band-edge energy (Ecb) of CdTe QDs, which will supply the excited electron with a more stable environment.

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