Exciton emission in PTCDA thin films under uniaxial pressure

AbstractLight-induced halide segregation limits the bandgap tunability of mixed-halide perovskites for tandem photovoltaics. Here we report that light-induced halide segregation is strain-activated in MAPb(I1−xBrx)3 with Br concentration below approximately 50%, while it is intrinsic for Br concentration over approximately 50%. Free-standing single crystals of CH3NH3Pb(I0.65Br0.35)3 (35%Br) do not show halide segregation until uniaxial pressure is applied. Besides, 35%Br single crystals grown on lattice-mismatched substrates (e.g. single-crystal CaF2) show inhomogeneous segregation due to heterogenous strain distribution. Through scanning probe microscopy, the above findings are successfully translated to polycrystalline thin films. For 35%Br thin films, halide segregation selectively occurs at grain boundaries due to localized strain at the boundaries; yet for 65%Br films, halide segregation occurs in the whole layer. We close by demonstrating that only the strain-activated halide segregation (35%Br/45%Br thin films) could be suppressed if the strain is properly released via additives (e.g. KI) or ideal substrates (e.g. SiO2).

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Preparation of High-Quality CuInSe2 Thin Films by Molecular Beam Epitaxy

MRS Proceedings ◽

10.1557/proc-485-169 ◽

1997 ◽

Vol 485 ◽

Author(s):

B. H. Tseng ◽

S. B. Lin ◽

D. J. Yang

Keyword(s):

Thin Films ◽

Molecular Beam Epitaxy ◽

Thermal Annealing ◽

Molecular Beam ◽

Epitaxial Films ◽

Luminescence Properties ◽

High Quality ◽

Film Composition ◽

Exciton Emission ◽

Gaas Substrates

AbstractCuInSe2 epitaxial films having superior luminescence properties were prepared by using (001) GaAs substrates and then by thermal annealing in the presence of a Se-beam flux. We also found that exciton emission became dominant when the film composition was very close to the stoichiometry.

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First-principles study on the uniaxial pressure induced topological quantum phase transitions of Ge2X2Te5 (X =Sb, Bi) thin films

Acta Physica Sinica ◽

10.7498/aps.64.107301 ◽

2015 ◽

Vol 64 (10) ◽

pp. 107301

Author(s):

Zhang Mei ◽

Wen Li-Wei ◽

Ding Jun ◽

Zhang Ying

Keyword(s):

Thin Films ◽

Phase Transitions ◽

First Principles ◽

Quantum Phase Transitions ◽

Quantum Phase ◽

Uniaxial Pressure ◽

First Principles Study ◽

Topological Quantum

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Spectral narrowing of self-trapped exciton emission in anatase thin films

Thin Solid Films ◽

10.1016/s0040-6090(01)01494-8 ◽

2001 ◽

Vol 400 (1-2) ◽

pp. 130-133 ◽

Cited By ~ 22

Author(s):

V Kiisk ◽

I Sildos ◽

A Suisalu ◽

J Aarik

Keyword(s):

Thin Films ◽

Exciton Emission ◽

Spectral Narrowing

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Oxygen Optical Sensing in Gas and Liquids with Nanostructured ZnO Thin Films Based on Exciton Emission Detection

The Journal of Physical Chemistry C ◽

10.1021/jp5026027 ◽

2014 ◽

Vol 118 (18) ◽

pp. 9852-9859 ◽

Cited By ~ 34

Author(s):

Juan Ramón Sanchez-Valencia ◽

María Alcaire ◽

Pablo Romero-Gómez ◽

Manuel Macias-Montero ◽

Francisco J. Aparicio ◽

...

Keyword(s):

Thin Films ◽

Optical Sensing ◽

Zno Thin Films ◽

Exciton Emission ◽

Emission Detection

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Exciton emission of crystalline Zn(S)Se thin films arranged in microcavities based on amorphous insulating coatings

Semiconductors ◽

10.1134/s1063782616010115 ◽

2016 ◽

Vol 50 (1) ◽

pp. 8-15

Author(s):

V. I. Kozlovsky ◽

V. S. Krivobok ◽

P. I. Kuznetsov ◽

S. N. Nikolaev ◽

E. E. Onistchenko ◽

...

Keyword(s):

Thin Films ◽

Exciton Emission

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The study of interfacial reactions of nickel thin films on GaAs

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100074616 ◽

1983 ◽

Vol 41 ◽

pp. 156-157

Author(s):

L.J. Chen ◽

Y.F. Hsieh

Keyword(s):

Thin Films ◽

Integrated Circuits ◽

Interfacial Reactions ◽

Metal Contacts ◽

Nickel Thin Films ◽

Thin Foils ◽

The Status ◽

Si Doped ◽

Electron Microscopes

One measure of the maturity of a device technology is the ease and reliability of applying contact metallurgy. Compared to metal contact of silicon, the status of GaAs metallization is still at its primitive stage. With the advent of GaAs MESFET and integrated circuits, very stringent requirements were placed on their metal contacts. During the past few years, extensive researches have been conducted in the area of Au-Ge-Ni in order to lower contact resistances and improve uniformity. In this paper, we report the results of TEM study of interfacial reactions between Ni and GaAs as part of the attempt to understand the role of nickel in Au-Ge-Ni contact of GaAs.N-type, Si-doped, (001) oriented GaAs wafers, 15 mil in thickness, were grown by gradient-freeze method. Nickel thin films, 300Å in thickness, were e-gun deposited on GaAs wafers. The samples were then annealed in dry N2 in a 3-zone diffusion furnace at temperatures 200°C - 600°C for 5-180 minutes. Thin foils for TEM examinations were prepared by chemical polishing from the GaA.s side. TEM investigations were performed with JE0L- 100B and JE0L-200CX electron microscopes.

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Studies on Water in the Hydration Chamber of a Modified Electron Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069715 ◽

1970 ◽

Vol 28 ◽

pp. 544-545

Author(s):

R. C. Moretz ◽

G. G. Hausner ◽

D. F. Parsons

Keyword(s):

Thin Film ◽

Thin Films ◽

Electron Microscope ◽

Steady State ◽

Room Temperature ◽

Small Mass ◽

Equilibrium Pressure ◽

Biological Objects ◽

Mechanical Pump ◽

Differential Pumping

Use of the electron microscope to examine wet objects is possible due to the small mass thickness of the equilibrium pressure of water vapor at room temperature. Previous attempts to examine hydrated biological objects and water itself used a chamber consisting of two small apertures sealed by two thin films. Extensive work in our laboratory showed that such films have an 80% failure rate when wet. Using the principle of differential pumping of the microscope column, we can use open apertures in place of thin film windows.Fig. 1 shows the modified Siemens la specimen chamber with the connections to the water supply and the auxiliary pumping station. A mechanical pump is connected to the vapor supply via a 100μ aperture to maintain steady-state conditions.

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Nucleation and Early Growth of Sputtered thin Films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069570 ◽

1970 ◽

Vol 28 ◽

pp. 516-517

Author(s):

Dudley M. Sherman ◽

Thos. E. Hutchinson

Keyword(s):

Thin Films ◽

Electron Beam ◽

Ion Beam ◽

Ion Source ◽

Water Cooling ◽

Stages Of Growth ◽

Lens Assembly ◽

Microscope Technique ◽

Ion Beam Sputter Deposition

The in situ electron microscope technique has been shown to be a powerful method for investigating the nucleation and growth of thin films formed by vacuum vapor deposition. The nucleation and early stages of growth of metal deposits formed by ion beam sputter-deposition are now being studied by the in situ technique.A duoplasmatron ion source and lens assembly has been attached to one side of the universal chamber of an RCA EMU-4 microscope and a sputtering target inserted into the chamber from the opposite side. The material to be deposited, in disc form, is bonded to the end of an electrically isolated copper rod that has provisions for target water cooling. The ion beam is normal to the microscope electron beam and the target is placed adjacent to the electron beam above the specimen hot stage, as shown in Figure 1.

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