Analysis of Spontaneous Subpeak Emission from the Guide Layers of the Ultraviolet‐B Laser Diode Structure Containing Composition‐Graded p‐AlGaN Cladding Layers

Sato, Kosuke; Yasue, Shinji; Ogino, Yousuke; Takeuchi, Tetsuya; Kamiyama, Satoshi; Akasaki, Isamu

doi:10.1002/pssa.201900864

Cited by 13 publications

(5 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…8). If we assume that half of the carriers injected into the waveguide layers, including the 2QWs, recombine in the Al 0.45 Ga 0.55 N guide layers, as indicated in a previous report 19) and which is not considered in the simulation or in Fig. 9, the η i estimated from the simulation becomes 3.3%-5.0% at the current density of 25-80 kA cm −2 , which includes the experimental result of 3.5%.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Analysis of carrier injection efficiency of AlGaN UV-B laser diodes based on the relationship between threshold current density and cavity length

Sato

Omori

Yamada

et al. 2021

Jpn. J. Appl. Phys.

Self Cite

View full text Add to dashboard Cite

The carrier injection efficiency η i of recently developed UV-B laser diodes (LDs) is estimated on the basis of fundamental calculations and measurements. A general procedure to estimate η i based on the relationship between the differential external quantum efficiency and the cavity length proves to be inadequate because of the large variation. To estimate η i without relying on the unstable output power, we analyze in detail how the threshold current density relates to the cavity length. By applying a light confinement factor of 3.5%, an internal loss of 10 cm−1, a current density of 0.56 kA cm−2 in the emission layers at zero gain, and a reflectivity of the mirror facet of 0.16, we estimate η i ≈ 3.5% for UV-B LDs. This low η i in UV-B LDs is due to unbalanced injection between electron and hole currents, which leads to electron overflow to the p-GaN side, as indicated by a simulation.

show abstract

Section: Resultsmentioning

confidence: 99%

“…6,14) By contrast, only a single report focuses on the carrier injection mechanism in UV-B LDs, and it does not clarify the value. 19) Therefore, the origin of the high J th in UV-B LDs is not clear, so further fundamental investigations are warranted to clarify the physics that determines η i and thereby reduce J th to improve UV-B LDs.…”

Section: Introductionmentioning

confidence: 99%

Analysis of carrier injection efficiency of AlGaN UV-B laser diodes based on the relationship between threshold current density and cavity length

Sato

Omori

Yamada

et al. 2021

Jpn. J. Appl. Phys.

Self Cite

View full text Add to dashboard Cite

show abstract

“…An additional graded AlGaN contact layer is inserted to reduce the contact resistance. Utilizing this type of device architecture, Sato et al tentatively demonstrated an electrically pumped 298 nm UV LD with a current density of 41.2 kA cm −2 [33,96,97]. The optical mode confinement factor was calculated to be 3.5%, as shown in figure 12(b).…”

Section: Graded Algan Structures For Uv Ld Implementationmentioning

confidence: 99%

Compositionally graded III-nitride alloys: building blocks for efficient ultraviolet optoelectronics and power electronics

Zhang¹,

Huang²,

Song³

et al. 2021

Rep. Prog. Phys.

130

View full text Add to dashboard Cite

Wide bandgap aluminum gallium nitride (AlGaN) semiconductor alloys have established themselves as the key materials for building ultraviolet (UV) optoelectronic and power electronic devices. However, further improvements to device performance are lagging, largely due to the difficulties in precisely controlling carrier behavior, both carrier generation and carrier transport, within AlGaN-based devices. Fortunately, it has been discovered that instead of using AlGaN layers with fixed Al compositions, by grading the Al composition along the growth direction, it is possible to (1) generate high-density electrons and holes via polarization-induced doping; (2) manipulate carrier transport behavior via energy band modulation, also known as ‘band engineering’. Consequently, such compositionally graded AlGaN alloys have attracted extensive interest as promising building blocks for efficient AlGaN-based UV light emitters and power electronic devices. In this review, we focus on the unique physical properties of graded AlGaN alloys and highlight the key roles that such graded structures play in device exploration. Firstly, we elaborate on the underlying mechanisms of efficient carrier generation and transport manipulation enabled by graded AlGaN alloys. Thereafter, we comprehensively summarize and discuss the recent progress in UV light emitters and power electronic devices incorporating graded AlGaN structures. Finally, we outline the prospects associated with the implementation of graded AlGaN alloys in the pursuit of high-performance optoelectronic and power electronic devices.

show abstract

“…As a widely used disinfection product, the deep ultraviolet light-emitting device could be further developed [8]. Deep ultraviolet laser diodes (DUV-LDs) have the advantages of small size, lightweight, high conversion efficiency, high reliability, and easy light source assembly [9][10][11]. However, due to the high dislocation density in AlGaN materials, spontaneous and piezoelectric polarization field effects, and weak carrier confinement, DUV-LDs with wavelengths less than 280 nm still have the problems of low hole concentration, serious carrier leakage, and low radiation recombination rate and output power [12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Optimization of AlGaN-Based Deep Ultraviolet Laser Diodes with Graded Rectangular Superlattice Electron Blocking Layer and Graded Trapezoidal Superlattice Hole Blocking Layer

et al. 2022

View full text Add to dashboard Cite

To improve the carrier confinement capability and optimize the performance of deep ultraviolet laser diodes (DUV-LDs), we propose the graded rectangular superlattice (GRSL) electron blocking layer (EBL) and the graded trapezoidal superlattice (GTSL) hole blocking layer (HBL) in this paper. Crosslight software is used to simulate and compare the DUV-LDs with rectangular superlattice (RSL) EBL and RSL HBL, GRSL EBL and GRSL HBL, and GRSL EBL and GTSL HBL. The simulation results indicate that GRSL EBL and GTSL HBL increase the carrier concentration in the quantum wells, reduce the electron leakage in the p-type region and the hole leakage in the n-type region, increase the radiation recombination rate, reduce the threshold voltage and threshold current, and increase the electro-optical conversion efficiency and output power of DUV-LDs more effectively.

show abstract

Analysis of Spontaneous Subpeak Emission from the Guide Layers of the Ultraviolet‐B Laser Diode Structure Containing Composition‐Graded p‐AlGaN Cladding Layers

Abstract: This is the author manuscript accepted for publication and has undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as

Cited by 13 publications

References 35 publications

Analysis of carrier injection efficiency of AlGaN UV-B laser diodes based on the relationship between threshold current density and cavity length

Analysis of carrier injection efficiency of AlGaN UV-B laser diodes based on the relationship between threshold current density and cavity length

Compositionally graded III-nitride alloys: building blocks for efficient ultraviolet optoelectronics and power electronics

Optimization of AlGaN-Based Deep Ultraviolet Laser Diodes with Graded Rectangular Superlattice Electron Blocking Layer and Graded Trapezoidal Superlattice Hole Blocking Layer

Contact Info

Product

Resources

About