A Critical Comparison Between Movpe and MBE Growth of III-V Nitride Semiconductor Materials for Opto-Electronic Device Applications

1998 ◽  
Vol 537 ◽  
Author(s):  
M.A.L. Johnson ◽  
Zhonghai Yu ◽  
J.D. Brown ◽  
F.A. Koeck ◽  
N.A. El-Masry ◽  
...  
Keyword(s):  
Electronic Device ◽  
Light Emitting Diode ◽  
Rf Plasma ◽  
Nitrogen Species ◽  
Active Nitrogen ◽  
Mbe Growth ◽  
Light Emitting ◽  
Device Applications ◽  
Materials Used ◽  
P Type

AbstractA systematic study of the growth and doping of GaN, AlGaN, and InGaN by both molecular beam epitaxy (MBE) and metal-organic vapor phase epitaxy (MOVPE) has been performed. Critical differences between the resulting epitaxy are observed in the p-type doping using magnesium as the acceptor species. MBE growth, using rf-plasma sources to generate the active nitrogen species for growth, has been used for III-Nitride compounds doped either n-type with silicon or p-type with magnesium. Blue and violet light emitting diode (LED) test structures were fabricated. These vertical devices required a relatively high forward current and exhibited high leakage currents. This behavior was attributed to parallel shorting mechanisms along the dislocations in MBE grown layers. For comparison, similar devices were fabricated using a single wafer vertical flow MOVPE reactor and ammonia as the active nitrogen species. MOVPE grown blue LEDs exhibited excellent forward device characteristics and a high reverse breakdown voltage. We feel that the excess hydrogen, which is present on the GaN surface due to the dissociation of ammonia in MOVPE, acts to passivate the dislocations and eliminate parallel shorting for vertical device structures. These findings support the widespread acceptance of MOVPE, rather than MBE, as the epitaxial growth technique of choice for III-V nitride materials used in vertical transport bipolar devices for optoelectronic applications.

scholarly journals A Critical Comparison Between MOVPE and MBE Growth of III-V Nitride Semiconductor Materials for Opto-Electronic Device Applications

1999 ◽  
Vol 4 (S1) ◽  
pp. 594-599 ◽  
Author(s):  
M.A.L. Johnson ◽  
Zhonghai Yu ◽  
J.D. Brown ◽  
F.A. Koeck ◽  
N.A. El-Masry ◽  
...  
Keyword(s):  
Electronic Device ◽  
Light Emitting Diode ◽  
Rf Plasma ◽  
Nitrogen Species ◽  
Active Nitrogen ◽  
Mbe Growth ◽  
Light Emitting ◽  
Device Applications ◽  
Materials Used ◽  
P Type

A systematic study of the growth and doping of GaN, AlGaN, and InGaN by both molecular beam epitaxy (MBE) and metal-organic vapor phase epitaxy (MOVPE) has been performed. Critical differences between the resulting epitaxy are observed in the p-type doping using magnesium as the acceptor species. MBE growth, using rf-plasma sources to generate the active nitrogen species for growth, has been used for III-Nitride compounds doped either n-type with silicon or p-type with magnesium. Blue and violet light emitting diode (LED) test structures were fabricated. These vertical devices required a relatively high forward current and exhibited high leakage currents. This behavior was attributed to parallel shorting mechanisms along the dislocations in MBE grown layers. For comparison, similar devices were fabricated using a single wafer vertical flow MOVPE reactor and ammonia as the active nitrogen species. MOVPE grown blue LEDs exhibited excellent forward device characteristics and a high reverse breakdown voltage. We feel that the excess hydrogen, which is present on the GaN surface due to the dissociation of ammonia in MOVPE, acts to passivate the dislocations and eliminate parallel shorting for vertical device structures. These findings support the widespread acceptance of MOVPE, rather than MBE, as the epitaxial growth technique of choice for III-V nitride materials used in vertical transport bipolar devices for optoelectronic applications.

scholarly journals Unravelling the electron injection/transport mechanism in organic light-emitting diodes

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tsubasa Sasaki ◽  
Munehiro Hasegawa ◽  
Kaito Inagaki ◽  
Hirokazu Ito ◽  
Kazuma Suzuki ◽  
...  
Keyword(s):  
Work Function ◽  
Transport Mechanism ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Electron Injection ◽  
Organic Light Emitting Diodes ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Organic Light ◽  
Materials Used

AbstractAlthough significant progress has been made in the development of light-emitting materials for organic light-emitting diodes along with the elucidation of emission mechanisms, the electron injection/transport mechanism remains unclear, and the materials used for electron injection/transport have been basically unchanged for more than 20 years. Here, we unravelled the electron injection/transport mechanism by tuning the work function near the cathode to about 2.0 eV using a superbase. This extremely low-work function cathode allows direct electron injection into various materials, and it was found that organic materials can transport electrons independently of their molecular structure. On the basis of these findings, we have realised a simply structured blue organic light-emitting diode with an operational lifetime of more than 1,000,000 hours. Unravelling the electron injection/transport mechanism, as reported in this paper, not only greatly increases the choice of materials to be used for devices, but also allows simple device structures.

scholarly journals Operando direct observation of spin-states and charge-trappings of blue light-emitting-diode materials in thin-film devices

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Fumiya Osawa ◽  
Kazuhiro Marumoto
Keyword(s):  
Blue Light ◽  
High Performance ◽  
Density Functional ◽  
Light Emitting Diode ◽  
Green Light ◽  
Spin States ◽  
Light Emitting ◽  
Full Color ◽  
Color Displays ◽  
Materials Used

Abstract Spin-states and charge-trappings in blue organic light-emitting diodes (OLEDs) are important issues for developing high-device-performance application such as full-color displays and white illumination. However, they have not yet been completely clarified because of the lack of a study from a microscopic viewpoint. Here, we report operando electron spin resonance (ESR) spectroscopy to investigate the spin-states and charge-trappings in organic semiconductor materials used for blue OLEDs such as a blue light-emitting material 1-bis(2-naphthyl)anthracene (ADN) using metal–insulator–semiconductor (MIS) diodes, hole or electron only devices, and blue OLEDs from the microscopic viewpoint. We have clarified spin-states of electrically accumulated holes and electrons and their charge-trappings in the MIS diodes at the molecular level by directly observing their electrically-induced ESR signals; the spin-states are well reproduced by density functional theory. In contrast to a green light-emitting material, the ADN radical anions largely accumulate in the film, which will cause the large degradation of the molecule and devices. The result will give deeper understanding of blue OLEDs and be useful for developing high-performance and durable devices.

Polymer light-emitting diode with resistivity optimized p-type Si anode

2017 ◽  
pp. 1327-1330
Author(s):  
Qiaoli Niu ◽  
Hengsheng Wu ◽  
Yongtao Gu ◽  
Yanzhao Li ◽  
Wenjin Zeng ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Light Emitting ◽  
Si Anode ◽  
Polymer Light Emitting Diode ◽  
P Type

A Monolithic White-Light LED Based on GaN Doped with Be

2014 ◽  
Vol 93 ◽  
pp. 264-269 ◽  
Author(s):  
Henryk Teisseyre ◽  
Michal Bockowski ◽  
Toby David Young ◽  
Szymon Grzanka ◽  
Yaroslav Zhydachevskii ◽  
...  
Keyword(s):  
Gallium Nitride ◽  
White Light ◽  
Light Emission ◽  
Light Emitting Diode ◽  
Yellow Emission ◽  
Bulk Crystals ◽  
Light Emitting ◽  
Type Conductivity ◽  
P Type ◽  
Colour Rendering

In this communication, the use of gallium nitride doped with beryllium as an efficient converter for white light emitting diode is proposed. Until now beryllium in this material was mostly studied as a potential p-type dopant. Unfortunately, the realization of p-type conductivity in such a way seems impossible. However, due to a very intensive yellow emission, bulk crystals doped with beryllium can be used as light converters. In this communication, it is demonstrated that realisation of such diode is possible and realisation of a colour rendering index is close to that necessary for white light emission.

scholarly journals Extreme electron polaron spatial delocalization in π-conjugated materials

2015 ◽  
Vol 112 (45) ◽  
pp. 13779-13783 ◽  
Author(s):  
Jeff Rawson ◽  
Paul J. Angiolillo ◽  
Michael J. Therien
Keyword(s):  
Performance Metrics ◽  
Electronic Device ◽  
Conjugated Materials ◽  
Light Emitting ◽  
Spin Resonance ◽  
Spatial Dimensions ◽  
Device Applications ◽  
Charge Transfer Reactions ◽  
Reorganization Energies ◽  
Electron Reduction

The electron polaron, a spin-1/2 excitation, is the fundamental negative charge carrier in π-conjugated organic materials. Large polaron spatial dimensions result from weak electron-lattice coupling and thus identify materials with unusually low barriers for the charge transfer reactions that are central to electronic device applications. Here we demonstrate electron polarons in π-conjugated multiporphyrin arrays that feature vast areal delocalization. This finding is evidenced by concurrent optical and electron spin resonance measurements, coupled with electronic structure calculations that suggest atypically small reorganization energies for one-electron reduction of these materials. Because the electron polaron dimension can be linked to key performance metrics in organic photovoltaics, light-emitting diodes, and a host of other devices, these findings identify conjugated materials with exceptional optical, electronic, and spintronic properties.

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