The advantages of blue InGaN light-emitting diodes (LEDs) with barriers are studied. L-I curves, carrier concentrations in the quantum wells, energy band diagrams, and internal efficiency investigated. simulation results show that InGaN/InGaN LED has better performance over its conventional InGaN/GaN counterpart due to enhancement electron confinement, reduced polarization effect between barrier well, lower potential height for holes transport active region. also suggest droop is markedly...

Some specific designs on the electron blocking layer (EBL) of blue InGaN LEDs are investigated numerically in order to improve hole injection efficiency without losing capability electrons. Simulation results show that polarization-induced downward band bending is mitigated these redesigned EBLs and, hence, increases markedly. The optical performance and droop also improved, especially under situation high current injection.

Carrier transport characteristics of AlGaN-based deep-ultraviolet light-emitting diodes (LEDs) are theoretically investigated. Simulation results reveal that hole transport/injection may be severely obstructed by the large potential barrier at p-electron-blocking layer/p-GaN interface. Under this circumstance, slope efficiency degrades and electron leakage increases accordingly. By inserting AlGaN interlayers to form band-engineered staircase p-region, both holes I-V characteristic improved....

Efficiency enhancement of the blue InGaN light-emitting diodes (LEDs) with InGaN-AlGaN-InGaN barriers is studied numerically. The energy band diagrams, carrier concentrations in quantum wells, radiative recombination rate active region, light-current performance curves, and internal efficiency are investigated. simulation results suggest that InGaN/InGaN-AlGaN-InGaN LED has better over its conventional InGaN/GaN InGaN/InGaN counterparts due to appropriately modified which caused mainly by...

The advantages of InGaN light-emitting diodes with GaN-InGaN-GaN barriers are studied. energy band diagrams, carrier concentrations in the quantum wells, radiative recombination rate active region, light-current performance curves, and internal efficiency investigated. simulation results show that InGaN/GaN-InGaN-GaN diode has better over its conventional InGaN/GaN InGaN/InGaN counterparts due to appropriately modified diagrams which favorable for injection electrons holes uniform...

The advantages of blue InGaN light-emitting diodes (LEDs) with AlGaN barriers are studied numerically. performance curves, energy band diagrams, electrostatic fields, and carrier concentrations investigated. simulation results show that the InGaNAlGaN LED has better than its conventional InGaNGaN counterpart owing to increase hole injection enhancement electron confinement. also suggest efficiency droop is markedly improved when traditional GaN replaced by barriers.

The influence of piezoelectric polarization on the performance p-on-n (0001)-face GaN/InGaN p-i-n solar cells is investigated. Simulation results show that energy band tilted into direction detrimental for carrier collection due to polarization-induced electric field. When indium composition InGaN layer increases, this unfavorable effect becomes more serious which, in turn, deteriorates device performance. This discovery demonstrates that, besides issue crystal quality, problem caused by...

The band-engineered structure design for electron-blocking layer (EBL) and hole-blocking (HBL) in Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>x</i></sub> Ga xmlns:xlink="http://www.w3.org/1999/xlink">1–<i>x</i></sub> N-based ultraviolet light-emitting diodes (UV LEDs) is performed analyzed theoretically. Simulation results show that the severe polarization effect efficiently mitigated downward-bended band profile of EBL improved when...

The optical performance and relevant physical properties of near-ultraviolet (NUV) GaN-based light-emitting diodes (LEDs) are investigated. Specifically, the influence traditional AlGaN bulk electron blocking layer (EBL) AlGaN/GaN superlattice (SL) EBL with various thicknesses layers on NUV LEDs is explored. It indicated from band diagrams, electrostatic field profile, reflecting hole transmitting spectra, carrier concentrations profile that use a thin SL beneficial to confinement injection...

The polarization effect in AlGaN-based deep-ultraviolet (DUV) light-emitting diodes (LEDs) is investigated, which critical for the development of DUV LEDs, because basal material, epitaxial structure, and characteristics are very distinct to those well-developed (In)GaN-based near-ultraviolet visible light emitters. In this paper, influence multi-quantum well active region p-type layers on LEDs with Ga-face or N-face explored. Simulation results show that severe band bending induced by field...

Characteristics of deep-ultraviolet (DUV) light-emitting diodes (LEDs) are investigated. DUV LEDs possess severe electron current leakage due to insufficient carrier confinement the active region. Simply increasing Al composition quantum barriers (QBs) or electron-blocking layer (EBL) enlarge relevant potential barrier height would arise unexpected detrimental effects, such as extra polarization effect more obstruction for hole injection. In this paper, band-engineered composition-graded QBs...

Specific designs on the last barrier of near-ultraviolet InGaN light-emitting diodes are investigated numerically in order to diminish electron leakage current without sacrificing injection efficiency holes. Due reduction current, recombination electrons and holes <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">p</i> -layers is decreased and, thus, more can be injected into active region. The simulation results show that optical performance...

In this study, a green InGaN light-emitting diode with asymmetric AlGaN composition-graded barriers and without the use of an electron blocking layer is presented to possess markedly enhanced optical electrical performance. The simulation results show that output power increased by 10.0% 33.2%, which corresponds increment 7% 29.4% in internal quantum efficiency, at 100 mA when conventional GaN are replaced commonly used removed. suggest improved device performance due mainly injection holes...

GaN/InGaN p-i-n solar cells with N-face are simulated. In contrast to the detrimental effect of normal polarization, internal electric field induced by reversed polarization enhances efficiency carrier collection enlarging energy band tilting favorable direction in InGaN absorption layer. This beneficial becomes more remarkable when indium composition layer is higher.

The photovoltaic properties of (0001) face GaN/InGaN p-i-n solar cell are studied numerically. simulation results show that the detrimental effects hetero-interfaces and polarization charges will seriously degrade performance, especially when indium composition is high. If these not eliminated or diminished, would be good enough for practical applications even if a high-quality crystal could obtained. For this purpose, step-graded interlayers between GaN-InGaN interfaces introduced in order...

The influences of bandgap energy and polarization the electron blocking layer (EBL) in near-ultraviolet light-emitting diodes (NUV LEDs) are systematically investigated. Design curves for output power NUV LEDs as a function EBL provided. simulation results show that, when increases, polarization-induced charge increase accordingly. Both mechanisms have opposite effects confining electrons. with an large or small improved performance due to enhanced efficiency hole injection.

The photovoltaic characteristics of Ga-face GaN/InGaN p-i-n solar cells are investigated numerically. severe polarization and barrier effects induced by the hetero-interfaces demonstrated to be detrimental for carrier collection. conversion efficiency could degraded out application when degree and/or indium composition high. To efficiently eliminate both critical issues, cell structure with appropriate band engineering is introduced. In proposed structure, not only show high-grade...

Optical and electrical performance the relevant physical properties of deep ultraviolet (DUV) AlGaN-based light-emitting diodes (LEDs) are numerically investigated. The influence bulk AlGaN electron-blocking layer (EBL) with various Al compositions Mg-doping concentrations on output DUV LEDs is systemically explored. Simulation results show that LED <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.85</sub> Ga...

In deep-ultraviolet (DUV) light-emitting diodes (LEDs), it is difficult to obtain both efficient carrier confinement and high light extraction, which are quite sensitive optical polarization other physical parameters. this paper, characteristics of DUV LEDs with various n-AlGaN layers quantum barriers (QBs), widths wells (QWs) investigated. Specifically, the capability properties analyzed in detail. The simulation results show that LED structure Al <sub...

For InGaN laser diodes with emission wavelengths longer than 435 nm, the threshold current density usually increases number of well layers. This phenomenon could be attributed to dissociation high indium content layer at a growth temperature 750 °C due pressure. In this article, performance blue diode structures have been numerically investigated technology integrated program simulation program. The results suggest that inhomogeneous hole distribution in quantum wells also plays an important...

The impact of the polarization compensation InGaN interlayer between heterolayers Ga-face GaN/InGaN p-i-n solar cells is investigated numerically. Because enhancement carrier collection efficiency, conversion efficiency improved markedly, which can be ascribed to both reduction polarization-induced electric field in absorption layer and mitigation potential barriers at heterojunctions. This beneficial effect more remarkable situations with higher polarization, such as devices a lower degree...

The phenomenon of efficiency droop in blue InGaN light-emitting diodes (LEDs) is studied numerically. Simulation results indicate that the severe Auger recombination one critical mechanism corresponding to degraded under high current injection. To solve this issue, LED structure with thin AlGaN barriers and without use an EBL proposed. purpose strain-compensation mitigate strain accumulation a multiquantum well (MQW) active region thin-barrier structure. With proposed structure, hole...

Abstract Blue InGaN light‐emitting diodes (LEDs) with composition‐graded barriers and composition‐garded electron‐blocking layer (EBL) are studied theoretically. Simulation results show that the employment of compositon‐graded EBL simultaneously can benefit from enhanced hole‐injection efficiency more uniform carrier distribution among quantum wells. Moreover, optical electrical properties blue LEDs markedly promoted. The graded investigated systematically in an attempt to obtain optimal situation.

A four-junction InGaN-based multijunction solar cell structure is proposed theoretically. The simulation results show that, with the use of appropriately designed compositional grading layers, performance can be maintained without cost in degradation caused by polarization-induced electric field and potential barriers resulting from heterointerfaces. After optimization thicknesses for current matching, a high conversion efficiency 46.45% achieved under 1000-sun AM1.5D illumination, which...

The effect of using polarization-reversed AlInGaN-based quantum well active region in ultraviolet light-emitting diode is numerically investigated. By employing Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.54</sub> In xmlns:xlink="http://www.w3.org/1999/xlink">0.26</sub> Ga xmlns:xlink="http://www.w3.org/1999/xlink">0.20</sub> N and xmlns:xlink="http://www.w3.org/1999/xlink">0.83</sub>...