Steven P. DenBaars
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View article: Green (524 nm) InGaN/GaN laser diodes with nano-porous cladding and deep-ridge waveguiding
Green (524 nm) InGaN/GaN laser diodes with nano-porous cladding and deep-ridge waveguiding Open
View article: Improved efficiency of semipolar micro-LEDs enabled by epitaxial lateral overgrowth
Improved efficiency of semipolar micro-LEDs enabled by epitaxial lateral overgrowth Open
Semipolar epitaxial lateral overgrowth (ELO) is a promising technique to reduce crystalline defects and enhance the performance of micro-light-emitting diodes ( μ LEDs). In this work, we demonstrate that semipolar ELO μ LEDs outperform the…
View article: Recent Advancements in N-polar GaN HEMT Technology
Recent Advancements in N-polar GaN HEMT Technology Open
N-polar GaN HEMT technology has emerged as a disruptive technology that outperforms Ga-polar GaN HEMTs in terms of high-frequency power amplification capability. In this paper, the authors present a comprehensive review of the evolution of…
View article: Impact of threading dislocations on the V-defect assisted lateral carrier injection and recombination in InGaN quantum well LEDs
Impact of threading dislocations on the V-defect assisted lateral carrier injection and recombination in InGaN quantum well LEDs Open
The nonuniform hole distribution between InGaN quantum wells (QWs) of light emitting diodes (LEDs) has a negative impact on LED efficiency. The uniformity can be increased by using lateral hole injection through sidewalls of V-defects, whi…
View article: Origin of reduced efficiency in GaN-based micro-LEDs studied by scanning near-field optical microscopy
Origin of reduced efficiency in GaN-based micro-LEDs studied by scanning near-field optical microscopy Open
The quantum efficiency of micro-light emitting diodes (micro-LEDs) is lower than that of large area LEDs. This efficiency reduction is typically attributed to the nonradiative Shockley–Read–Hall recombination at the surface defects and cur…
View article: Micro-LED-based quantum random number generators
Micro-LED-based quantum random number generators Open
Quantum random number generators (QRNGs) leverage the inherent unpredictability of quantum mechanical phenomena to produce random numbers. However, the performance of many QRNGs is hindered by limitations such as low generation rates and t…
View article: Characterization of long-cavity GaN vertical-cavity surface-emitting lasers with a topside dielectric lens
Characterization of long-cavity GaN vertical-cavity surface-emitting lasers with a topside dielectric lens Open
We present a high-performance GaN-based vertical-cavity surface-emitting laser with a long cavity (70 λ ), nanoporous GaN distributed Bragg reflector (DBR), and topside dielectric lens, achieving room-temperature continuous-wave operation …
View article: 10.4% external quantum efficiency 294 nm UV LEDs at 20 A/cm<sup>2</sup> with a fully transparent tunnel junction
10.4% external quantum efficiency 294 nm UV LEDs at 20 A/cm<sup>2</sup> with a fully transparent tunnel junction Open
We report on the successful demonstration of an all metalorganic chemical vapor deposition (MOCVD) grown fully transparent tunnel junction (TJ) germicidal UV LED, resulting from the use of a lightly doped n - -AlGaN contact layer enabling …
View article: Increasing light extraction efficiency for UV LEDs with a low coverage p-GaN hole injection layer
Increasing light extraction efficiency for UV LEDs with a low coverage p-GaN hole injection layer Open
We report on the use of ultrathin low-coverage p-GaN hole injection islands on the top surface to improve the light extraction in UV LEDs, resulting in world-record UVB AlGaN UV LEDs emitting at 300 and 310 nm. With the optimization of the…
View article: High-Q, size-independent, and reconfigurable optical antennas via zero-index material dispersion engineering
High-Q, size-independent, and reconfigurable optical antennas via zero-index material dispersion engineering Open
Enhancing light-matter interactions at the nanoscale is foundational to nanophotonics, with epsilon near zero (ENZ) materials demonstrating significant potential.High-quality (Q) factor resonances maximizing these interactions are typicall…
View article: Volumetric carrier injection in InGaN quantum well light emitting diodes
Volumetric carrier injection in InGaN quantum well light emitting diodes Open
InGaN/GaN quantum well (QW) light emitting diodes (LEDs) are essential components of solid-state lighting and displays. However, the efficiency of long wavelength (green to red) devices is inferior to that of blue LEDs. To a large degree, …
View article: Demonstration of UV-A stimulated emission from optical pumping with a nano-porous cladding layer
Demonstration of UV-A stimulated emission from optical pumping with a nano-porous cladding layer Open
We report a room-temperature ultraviolet-A (UV-A) stimulated emission from a multiple-quantum-well laser diode featuring a nano-porous bottom cladding layer on the GaN substrate. For a 1500×15 μ m ridge-type edge-emitting laser, we achieve…
View article: Properties of V-defect injectors in long wavelength GaN LEDs studied by near-field electro- and photoluminescence
Properties of V-defect injectors in long wavelength GaN LEDs studied by near-field electro- and photoluminescence Open
The efficiency of multiple quantum well (QW) light emitting diodes (LEDs) to a large degree depends on uniformity of hole distribution between the QWs. Typically, transport between the QWs takes place via carrier capture into and thermioni…
View article: Enhanced optical gain of c-plane InGaN laser diodes via a strain relaxed template with reduced threading dislocation density
Enhanced optical gain of c-plane InGaN laser diodes via a strain relaxed template with reduced threading dislocation density Open
In this work, we demonstrate a method to reduce the threading dislocation density (TDD) of the previously reported strain relaxed template (SRT) on c -plane. Through the processes of nano-patterning/etching and epitaxial lateral overgrowth…
View article: Advances in InGaN-based RGB micro-light-emitting diodes for AR applications: Status and perspective
Advances in InGaN-based RGB micro-light-emitting diodes for AR applications: Status and perspective Open
Micro-light-emitting diodes (µLEDs) are gathering significant interest as a technology for emerging micro-displays. However, µLEDs encounter numerous obstacles, including size-dependent efficiency loss, poor efficiency of red µLEDs, and ch…
View article: Carrier diffusion in long wavelength InGaN quantum well LEDs after injection through V-defects
Carrier diffusion in long wavelength InGaN quantum well LEDs after injection through V-defects Open
The efficiency of operation of GaN-based light emitting diodes (LEDs) to a large degree relies on realization of a uniform hole distribution between multiple quantum wells (QWs) of the active region. Since the direct thermionic transport b…
View article: Pure edge-dislocation half-loops in low-temperature <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><mml:mrow><mml:mi>Ga</mml:mi><mml:mi mathvariant="normal">N</mml:mi></mml:mrow></mml:math> for V-defect formation
Pure edge-dislocation half-loops in low-temperature for V-defect formation Open
Lateral injection of carriers through semipolar crystallographic planes into c-plane QWs is one of the new frontiers in $\mathrm{III}$-$\mathrm{N}$ light-emitting diodes (LEDs), especially for long wavelengths. Strategic use of V-defects h…
View article: Blue GaN-based DFB laser diode with sub-MHz linewidth
Blue GaN-based DFB laser diode with sub-MHz linewidth Open
Distributed feedback laser diodes (DFBs) serve as simple, compact, narrow-band light sources supporting a wide range of photonic applications. Typical linewidths are on the order of sub-MHz for free-running III-V DFBs at infrared wavelengt…
View article: III-nitride m-plane violet narrow ridge edge-emitting laser diodes with sidewall passivation using atomic layer deposition
III-nitride m-plane violet narrow ridge edge-emitting laser diodes with sidewall passivation using atomic layer deposition Open
A novel deep-ridge laser structure with atomic-layer deposition (ALD) sidewall passivation was proposed that enhances the optical characteristics of 8-µm ridge width III-nitride violet lasers on freestanding m -plane GaN substrates. The in…
View article: Erratum: “Planarization of <i>p</i>-GaN surfaces on MOCVD grown V-defect engineered GaN-based LEDs” [Appl. Phys. Lett. <b>124</b>, 172102 (2024)]
Erratum: “Planarization of <i>p</i>-GaN surfaces on MOCVD grown V-defect engineered GaN-based LEDs” [Appl. Phys. Lett. <b>124</b>, 172102 (2024)] Open
View article: Dynamics of carrier injection through V-defects in long wavelength GaN LEDs
Dynamics of carrier injection through V-defects in long wavelength GaN LEDs Open
The efficiency of high-power operation of multiple quantum well (QW) light emitting diodes (LEDs) to a large degree depends on the realization of uniform hole distribution between the QWs. In long wavelength InGaN/GaN QW LEDs, the thermion…
View article: Optical analysis of III-nitride micro-light-emitting diodes with different sidewall treatments at low current density operation
Optical analysis of III-nitride micro-light-emitting diodes with different sidewall treatments at low current density operation Open
In this work, the optical efficiency of III-nitride blue micro-LEDs ( μ LEDs) ranged from 5 × 5 to 60 × 60 μ m 2 with different sidewall treatments at low current density range was investigated. The results showed dielectric sidewall passi…
View article: Trap Passivation for Reducing On-Resistance and Saturation Voltage in Wafer-Bonded InGaAs-Channel/GaN-Drain Vertical FETs
Trap Passivation for Reducing On-Resistance and Saturation Voltage in Wafer-Bonded InGaAs-Channel/GaN-Drain Vertical FETs Open
High frequency and high power are the driving forces behind semiconductor transistor technology. However, conventional devices have the tradeoff of either being high speed or high breakdown—but not both. Wafer-bonded current aperture verti…
View article: Demonstration of III-nitride vertical-cavity surface-emitting lasers with a topside dielectric curved mirror
Demonstration of III-nitride vertical-cavity surface-emitting lasers with a topside dielectric curved mirror Open
We report long cavity (65 λ ) GaN-based vertical-cavity surface-emitting lasers (VCSELs) with a topside dielectric concave mirror, an ion implanted current aperture, and a bottomside nanoporous GaN distributed Bragg reflector. Under pulsed…
View article: High external quantum efficiency (6.5%) InGaN V-defect LEDs at 600 nm on patterned sapphire substrates
High external quantum efficiency (6.5%) InGaN V-defect LEDs at 600 nm on patterned sapphire substrates Open
Highly efficient long-wavelength InGaN LEDs have been a research focus in nitride LEDs for their potential applications in displays and solid-state lighting. A key breakthrough has been the use of laterally injected quantum wells via natur…
View article: The micro-LED roadmap: status quo and prospects
The micro-LED roadmap: status quo and prospects Open
Micro light-emitting diode (micro-LED) will play an important role in the future generation of smart displays. They are found very attractive in many applications, such as maskless lithography, biosensor, augmented reality (AR)/mixed reali…
View article: Origins of the high-energy electroluminescence peaks in long-wavelength (∼495–685 nm) InGaN light-emitting diodes
Origins of the high-energy electroluminescence peaks in long-wavelength (∼495–685 nm) InGaN light-emitting diodes Open
We investigate the unexpected high-energy electroluminescence (EL) peaks observed in long-wavelength InGaN light-emitting diodes (LEDs) with ground state emission peaks between ∼495 and 685 nm by studying the EL spectra of LEDs with varyin…
View article: High external quantum efficiency (6.8%) UV-A LEDs on AlN templates with quantum barrier optimization
High external quantum efficiency (6.8%) UV-A LEDs on AlN templates with quantum barrier optimization Open
AlGaN-based UV-A LEDs have wide applications in medical treatment and chemical sensing; however, their efficiencies are still far behind visible LEDs or even shorter wavelengths UV-C counterparts because of the large lattice mismatch betwe…
View article: Long-Cavity M-Plane GaN-Based Vertical-Cavity Surface-Emitting Lasers with a Topside Monolithic Curved Mirror
Long-Cavity M-Plane GaN-Based Vertical-Cavity Surface-Emitting Lasers with a Topside Monolithic Curved Mirror Open
We report long-cavity (60.5 λ) GaN-based vertical-cavity surface-emitting lasers with a topside monolithic GaN concave mirror, a buried tunnel junction current aperture, and a bottomside nanoporous GaN distributed Bragg reflector. Under pu…
View article: Recovering the efficiency of AlGaInP red micro-LEDs using sidewall treatments
Recovering the efficiency of AlGaInP red micro-LEDs using sidewall treatments Open
A sidewall treatment process is proposed to recover the external quantum efficiency (EQE) loss in AlGaInP micro-LEDs ( μ LEDs). The proposed sidewall treatment consists of thermal annealing, ammonium sulfide chemical treatment, and sidewal…