scholarly journals Ultrahigh sensitivity of methylammonium lead tribromide perovskite single crystals to environmental gases

2016 ◽  
Vol 2 (7) ◽  
pp. e1600534 ◽  
Author(s):  
Hong-Hua Fang ◽  
Sampson Adjokatse ◽  
Haotong Wei ◽  
Jie Yang ◽  
Graeme R. Blake ◽  
...  
Keyword(s):  
Single Crystals ◽  
Surface Recombination ◽  
State Density ◽  
Limiting Factors ◽  
Surface Recombination Velocity ◽  
Photoluminescence Intensity ◽  
Trap State ◽  
Surface Trap ◽  
Design And Optimization ◽  
Surface Recombination Rate

One of the limiting factors to high device performance in photovoltaics is the presence of surface traps. Hence, the understanding and control of carrier recombination at the surface of organic-inorganic hybrid perovskite is critical for the design and optimization of devices with this material as the active layer. We demonstrate that the surface recombination rate (or surface trap state density) in methylammonium lead tribromide (MAPbBr3) single crystals can be fully and reversibly controlled by the physisorption of oxygen and water molecules, leading to a modulation of the photoluminescence intensity by over two orders of magnitude. We report an unusually low surface recombination velocity of 4 cm/s (corresponding to a surface trap state density of 108cm−2) in this material, which is the lowest value ever reported for hybrid perovskites. In addition, a consistent modulation of the transport properties in single crystal devices is evidenced. Our findings highlight the importance of environmental conditions on the investigation and fabrication of high-quality, perovskite-based devices and offer a new potential application of these materials to detect oxygen and water vapor.

scholarly journals Модификация электронных свойств поверхности n-InP(100) сульфидными растворами

2021 ◽  
Vol 55 (10) ◽  
pp. 895
Author(s):  
М.В. Лебедев ◽  
Т.В. Львова ◽  
А.Н. Смирнов ◽  
В.Ю. Давыдов
Keyword(s):  
Raman Spectroscopy ◽  
Electronic Properties ◽  
Electron Density ◽  
Surface Recombination ◽  
Depletion Layer ◽  
Surface Recombination Velocity ◽  
Photoluminescence Intensity ◽  
Surface Depletion ◽  
Recombination Velocity ◽  
Sulfide Solution

Photoluminescence and Raman spectroscopy are used to study the electronic properties of n-InP(100) surfaces passivated with different sulfide solutions. Such a passivation results in the increase in photoluminescence intensity of the semiconductor evidencing for the reduction in the surface recombination velocity. The increase in the photoluminescence intensity is accompanied by the narrowing of the surface depletion layer, as well as by the increase of the electron density in the probed volume of InP. The efficiency of electronic passivation of the n-InP(100) surface depends on the composition of the sulfide solution.

Photoluminescence Intensity Enhancement of GaAs by Vapor-Deposited GaS: a Rational Approach to Surface Passivation

1992 ◽  
Vol 282 ◽  
Author(s):  
Phillip P. Jenkins ◽  
Aloysius F. Hepp ◽  
Michael B. Power ◽  
Andrew R. Macinnes ◽  
Andrew R. Barrontt
Keyword(s):  
Surface Passivation ◽  
Surface Recombination ◽  
Chemical Vapor ◽  
Surface Recombination Velocity ◽  
Rational Approach ◽  
Cubic Phase ◽  
Photoluminescence Intensity ◽  
Band Bending ◽  
X Ray ◽  
Order Of Magnitude

ABSTRACTA two order-of-magnitude enhancement of photoluminescence intensity relative to untreated GaAs has been observed for GaAs surfaces coated with chemical vapor-deposited GaS. The increase in photoluminescence intensity can be viewed as an effective reduction in surface recombination velocity and/or band bending. The gallium cluster [(t-Bu)GaS]4 was used as a single-source precursor for the deposition of GaS thin films. The cubane core of the structurally-characterized precursor is retained in the deposited film producing a cubic phase. Furthermore, a near-epitaxial growth is observed for the GaS passivating layer. Films were characterized by transmission electron microscopy, X-ray powder diffraction, and X-ray photoelectron and Rutherford backscattering spectroscopies.

scholarly journals Low trap-state density and long carrier diffusion in organolead trihalide perovskite single crystals

Science ◽  
2015 ◽  
Vol 347 (6221) ◽  
pp. 519-522 ◽  
Author(s):  
D. Shi ◽  
V. Adinolfi ◽  
R. Comin ◽  
M. Yuan ◽  
E. Alarousu ◽  
...  
Keyword(s):  
Single Crystals ◽  
State Density ◽  
Trap State ◽  
Carrier Diffusion

Trap-Induced Dispersive Transport and Dielectric Loss in PbS Nanoparticle Films

2017 ◽  
Vol 231 (1) ◽  
Author(s):  
Alina Chanaewa ◽  
Katharina Poulsen ◽  
Alexander Gräfe ◽  
Christoph Gimmler ◽  
Elizabeth von Hauff
Keyword(s):  
Dielectric Loss ◽  
Deep Trap ◽  
State Density ◽  
Trap States ◽  
Trap State ◽  
Dispersive Transport ◽  
Surface Trap ◽  
Different Types ◽  
State Densities ◽  
Pbs Nanoparticle

AbstractIn this work, we investigate the electrical and dielectric response of lead sulfide (PbS) nanoparticle (NP) films with impedance spectroscopy. In particular, the influence of the ligand passivation on the surface trap state density of PbS NPs is demonstrated by comparing two different types of ligands: ethane-1,2-dithiol (EDT) and 3-sulfanylpropanoic acid (MPA). We observe that the MPA treatment passivates the PbS surface more efficiently than EDT. By analyzing the dielectric loss spectra, we are able to visualize shallow trap states in the bulk of PbS-EDT films and correlate this with the dispersive response observed in the impedance spectra. Evidence of deep trap states is revealed for both PbS-EDT and PbS-MPA diodes. Under illumination, the PbS-MPA and PbS-EDT films demonstrate almost identical trap profiles, showing solely the deep trap state densities. We conclude that the deep traps are related to the stoichiometry of the PbS NPs.

Temperature Dependence of the Carrier Lifetime in 4H-SiC Epilayers

2010 ◽  
Vol 645-648 ◽  
pp. 203-206 ◽  
Author(s):  
Paul B. Klein ◽  
Rachael L. Myers-Ward ◽  
Kok Keong Lew ◽  
Brenda L. VanMil ◽  
Charles R. Eddy ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Carrier Lifetime ◽  
Surface Recombination ◽  
Surface Trap ◽  
Surface Band ◽  
Lifetime Measurements ◽  
Band Bending ◽  
Deep Defect ◽  
Surface Recombination Rate ◽  
Recombination Processes

The temperature dependence of the carrier lifetime was measured in n-type 4H-SiC epilayers of varying Z1/2 deep defect concentrations and layer thicknesses in order to investigate the recombination processes controlling the carrier lifetime in low- Z1/2 material. The results indicate that in more recently grown layers with lower deep defect concentrations, surface recombination tends to dominate over carrier capture by other bulk defects. Low-injection lifetime measurements were also found to provide a convenient method to assess the surface band bending and surface trap density in samples with a significant surface recombination rate.

Electrochemical Sulfur Treatments of GaAs Using Na2S and (NH4)2S Solutions: A Surface Chemical Study

1992 ◽  
Vol 282 ◽  
Author(s):  
J. Yota ◽  
V. A. Burrows
Keyword(s):  
Electronic Properties ◽  
Photoelectron Spectroscopy ◽  
Surface Film ◽  
Surface Recombination ◽  
Chemical Study ◽  
Lower Surface ◽  
State Density ◽  
Gaas Surface ◽  
Surface Recombination Velocity ◽  
Recombination Velocity

ABSTRACTChemical sulfur treatments of GaAs have been shown to improve the GaAs surface electronic properties. These treatments result in lower surface state density, lower surface recombination velocity, and shifting or unpinning of the Fermi level, in addition to improvement in the performance of devices. However, there is still considerable controversy regarding the chemical nature of the surface film which results from this chemical sulfidation. It has been shown that this film is not stable chemically and electronically. The improved surface electronic properties decay with time and are sensitive to the chemical environment of the material. In this study, using surface infrared reflection spectroscopy (SIRS) and x-ray photoelectron spectroscopy (XPS), we have investigated the electrochemical sulfidation of GaAs as a possible new method to produce a GaAs surface that is stable chemically and electronically. We have found that anodic treatments with Na2S and (NH4S solutions result in the removal of the pre-existing oxide of GaAs and the formation of films comprising sulfur, sodium carbonate, ammonium thiosulfate, and sulfide and sulfur-oxygen compounds of arsenic. Rinsing the GaAs with water removes the bulk of the film, leaving behind a surface on which only arsenic sulfide was detected.

Analysis of Contaminated Oxide-Silicon Interfaces

2011 ◽  
Vol 178-179 ◽  
pp. 243-248
Author(s):  
Maria Luisa Polignano ◽  
Davide Codegoni ◽  
Luca Castellano ◽  
Stefano Greco ◽  
Gabriella Borionetti ◽  
...  
Keyword(s):  
Surface Segregation ◽  
Surface Recombination ◽  
Interface State ◽  
State Density ◽  
Surface Recombination Velocity ◽  
Organic Contamination ◽  
Conductance Method ◽  
The Impact ◽  
Silicon Interface ◽  
Dlts Spectra

Methods for the analysis of the oxide-silicon interface were compared for their ability to reveal metal segregation at the interface and organic contamination. The impact of these contaminations on surface recombination velocity measurements, on capacitance vs. voltage, conductance vs. voltage and capacitance vs. time measurements and on MOS-DLTS spectra was studied. Niobium-contaminated wafers were used as an example of metal surface segregation, because it was previously shown that niobium is prone to surface segregation. Interface state density measurements obtained by the conductance method showed a limited impact of niobium implantation. Vice versa significant effects were found in MOS-DLTS spectra. For what concerns organic contamination, MOS-DLTS showed the most significant effects from the point-of-view of the intrinsic properties of the silicon oxide - silicon interface, and GOI tests demonstrate a clear impact of the organic contamination on MOS capacitors oxide breakdown events.

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