scholarly journals The Effect of Trap States on the Optoelectronic Properties of Nanoporous Nickel Oxide

2019 ◽  
Vol 166 (5) ◽  
pp. H3265-H3270
Author(s):  
Ádám Balog ◽  
Csaba Janáky
Keyword(s):  
Nickel Oxide ◽  
Optoelectronic Properties ◽  
Trap States

scholarly journals Mid-gap Trap State Mediated Dark Current in Organic Photodiodes

2021 ◽  
Author(s):  
Christina Kaiser ◽  
Oskar Sandberg ◽  
Stefan Zeiske ◽  
Sam Gielen ◽  
Wouter Maes ◽  
...  
Keyword(s):  
Dark Current ◽  
Near Infrared ◽  
Low Cost ◽  
Open Circuit ◽  
Optoelectronic Properties ◽  
Consumer Electronics ◽  
Embodied Energy ◽  
Wearable Electronics ◽  
Trap States ◽  
New Applications

Abstract Photodiodes are ubiquitous in industry and consumer electronics. New applications for photodiodes are constantly emerging, such as the internet of things and wearable electronics that demand different mechanical and optoelectronic properties from those provided by conventional inorganic devices. This has stimulated considerable interest in the use of next generation semiconductors, particularly the organics, which provide a vast palette of available optoelectronic properties, can be incorporated into flexible form factor geometries, and promise extremely low cost, low embodied energy manufacturing from earth abundant materials. The sensitivity of a photodiode to low light intensities (typically important in these new applications) depends critically on the dark current. Organic photodiodes, however, are characterized by a much higher dark current than expected for thermally excited band-to-band transitions. Here, we show that the lower limit of the dark current is given by recombination via mid-gap trap states. This new insight is generated from temperature dependent dark current measurements of narrow-gap photodiodes for the near-infrared. Based on Shockley-Read-Hall statistics, a diode equation is derived which can be used to determine an upper limit for the specific detectivity and to explain the general trend observed for the light to dark current ratio as a function of the experimental open-circuit voltage for a series of organic photodiodes. A detailed understanding of the origins of noise in any detector is fundamental to defining performance limitations and thus is critical to materials and device selection, design and optimisation for all applications. Our work establishes these important principles for organic semiconductor photodiodes for the near-infrared.

Facet-controlled preparation of hybrid perovskite microcrystals in the gas phase and the remarkable effect on optoelectronic properties

CrystEngComm ◽  
2017 ◽  
Vol 19 (31) ◽  
pp. 4615-4621 ◽  
Author(s):  
T. Kollek ◽  
S. Polarz
Keyword(s):  
Gas Phase ◽  
Particle Shape ◽  
Optoelectronic Properties ◽  
Trap States ◽  
Surface Trap ◽  
Remarkable Effect ◽  
Hybrid Perovskite ◽  
Controlled Preparation

Particle shape of hybrid perovskite microcrystals influences PL properties via differences in the abundant facets and associated surface trap states.

Impact of Divalent Metal Additives on the Structural and Optoelectronic Properties of CH3NH3PbI3 Perovskite Prepared by the Two-Step Solution Process

MRS Advances ◽  
2017 ◽  
Vol 2 (21-22) ◽  
pp. 1183-1188 ◽  
Author(s):  
Suneth C. Watthage ◽  
Zhaoning Song ◽  
Niraj Shrestha ◽  
Adam B. Phillips ◽  
Geethika K. Liyanage ◽  
...  
Keyword(s):  
Grain Size ◽  
Deep Level ◽  
Control Sample ◽  
Solution Process ◽  
Deposition Process ◽  
Divalent Metal ◽  
Optoelectronic Properties ◽  
Trap States ◽  
Lead Iodide ◽  
Structural And Optoelectronic Properties

ABSTRACTHere, we investigate the effect of divalent metal (Zn2+, Cd2+ and Hg2+) on the structural and optoelectronic properties of methylammonium lead iodide perovskite materials prepared by the two-step deposition process. The incorporation of Cd2+ significantly improved the grain size, crystallinity, and charge carrier lifetime of CH3NH3PbI3. The inclusion of Hg2+ and Zn2+ improved the grain size compare to the control sample but adversely affected the optoelectronic properties of perovskite films. The Hg- and Zn-based impurities were formed on the surface of the films, which increased the charge trap density and lead to high non-radiative recombination rate. Time resolved photoluminescence measurements indicated that the Cd and Zn point defects do not create deep-level trap states, but the Zn-modified film showed a low lifetime due to morphology changes in the film and particle segregation on the surface.

The Microstructure of Nickel Oxide Scales

1981 ◽  
Vol 39 ◽  
pp. 86-87
Author(s):  
M. T. Tinker ◽  
L. W. Hobbs
Keyword(s):  
Electron Microscopy ◽  
Nickel Oxide ◽  
Ion Beam ◽  
Oxide Scales ◽  
Nickel Substrate ◽  
Outward Diffusion ◽  
Transmission Electron ◽  
Nickel Substrates ◽  
Nickel Base ◽  
Technological Interest

There is considerable technological interest in oxidation of nickel because of the importance of nickel-base superalloys in high-temperature oxidizing environments. NiO scales on nickel grow classically, by outward diffusion of nickel through the scale, and are among the most studied of oxidation systems. We report here the first extensive characterization by transmission electron microscopy of nickel oxide scales formed on bulk nickel substrates and sectioned both parallel and transversely to the Ni/NiO interface.Electrochemically-polished nickel sheet of 99.995% purity was oxidized at 1273 K in 0.1 MPa oxygen partial pressure for times between 5 s and 25 h. Parallel sections were produced using a combination of electropolishing of the nickel substrate and ion-beam thinning of the scale to any desired depth in the scale. Transverse sections were prepared by encasing stacked strips of oxidized nickel sheet in epoxy resin, sectioning transversely and ion-beam thinning until thin area spanning one or more interfaces was obtained.

HREM observation of NiO growth on submicron spheres of pure nickel

1989 ◽  
Vol 47 ◽  
pp. 548-549
Author(s):  
C.M. Teng ◽  
T.F. Kelly ◽  
J.P. Zhang ◽  
H.M. Lin ◽  
Y.W. Kim
Keyword(s):  
Nickel Oxide ◽  
Grain Boundaries ◽  
Pure Nickel ◽  
Submicron Particles ◽  
Crystal Formation ◽  
Nickel Wire ◽  
Liquid Droplets ◽  
Oxide Interface ◽  
Nickel Chromium ◽  
Chromium Alloys

Spherical submicron particles of materials produced by electrohydrodynamic (EHD) atomization have been used to study a variety of materials processes including nucleation of alternative crystallization phases in iron-nickel and nickel-chromium alloys, amorphous solidification in submicron droplets of pure metals, and quasi-crystal formation in nickel-chromium alloys. Some experiments on pure nickel, nickel oxide single crystals, the nickel/nickel(II) oxide interface, and grain boundaries in nickel monoxide have been performed by STEM. For these latter studies, HREM is the most direct approach to obtain particle crystal structures at the atomic level. Grain boundaries in nickel oxide have also been investigated by HREM. In this paper, we present preliminary results of HREM observations of NiO growth on submicron spheres of pure nickel.Small particles of pure nickel were prepared by EHD atomization. For the study of pure nickel, 0.5 mm diameter pure nickel wire (99.9975%) is sprayed directly in the EHD process. The liquid droplets solidify in free-flight through a vacuum chamber operated at about 10-7 torr.

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