Surfactant effects of indium on cracking in AlN/GaN distributed Bragg reflectors grown via metal organic vapor phase epitaxy

Rodak, L. E.; Miller, Christopher; Korakakis, D.

doi:10.1016/j.spmi.2010.11.001

Cited by 9 publications

(5 citation statements)

References 32 publications

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“…The fabrication starts with the growth of layers that make up the LED active regions using MOVPE techniques [38], [39]. The LED structure is grown on a sapphire substrate (430 μm thick) and is shown in the Fig.…”

Section: Device Fabricationmentioning

confidence: 99%

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Improvement in the Light Extraction of Blue InGaN/GaN-Based LEDs Using Patterned Metal Contacts

Kadiyala

Lee

Rodak

et al. 2014

IEEE J. Electron Devices Soc.

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We demonstrate a method to improve the light extraction from an LED using photonic crystal (PhC)-like structures in metal contacts. A patterned metal contact with an array of Silicon Oxide (SiO x ) pillars (440 nm in size) on an InGaN/GaNbased MQW LED has shown to increase output illumination uniformity through experimental characterization. Structural methods of improving light extraction using transparent contacts or dielectric photonic crystals typically require a tradeoff between improving light extraction and optimalelectrical characteristics.The method presented here provides an alternate solution to provide a 15% directional improvement (surface normal) in the radiation profile and ∼ 30% increase in the respective intensity profile without affecting the electrical characteristics of the device. Electron beam patterning of hydrogen silesquioxane (HSQ), a novel electron beam resist is used in patterning these metal contacts. After patterning, thermal curing of the patterned resist is done to form SiO x pillars. These SiO x pillars aid as a mask for transferring the pattern to the p-metal contact. Electrical and optical characterization results of LEDs fabricated with and without patterned contacts are presented. We present the radiation and intensity profiles of the planar and patterned devices extracted using Matlab-based image analysis technique from 200 μm (diameter) circular unpackaged LEDs.Index Terms-Electron beam lithography (EBL), light emitting diode (LED), patterning, photonic crystal (PC), hydrogen silesquioxane (HSQ).

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Section: Device Fabricationmentioning

confidence: 99%

“…1. [39], [38]. InGaN/GaN -based quantum wells with a periodicity of 11.90 nm (QW ∼ 4 nm, Barrier ∼ 8 nm) were grown with 16% indium concentration (In 0.16 Ga 0.94 N) on n-type (Silicon doped) GaN and followed by p-type (Magnesium doped) GaN.…”

Section: Device Fabricationmentioning

confidence: 99%

Improvement in the Light Extraction of Blue InGaN/GaN-Based LEDs Using Patterned Metal Contacts

Kadiyala

Lee

Rodak

et al. 2014

IEEE J. Electron Devices Soc.

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“…7 Lack of low-cost and highquality GaN substrates has necessitated epitaxy on mismatched substrates, leading to large defect densities. 9 The large lattice mismatch between GaN and AlN has prevented the realization of high quality Bragg mirrors 10 and low threshold vertical cavity surface emitting lasers (VCSELs) 6 and electrically pumped polariton lasers, 11,12 where such mirrors are needed. Ga(In)N nanowires can be epitaxially grown without a catalyst on (001) or (111) silicon substrate in the wurtzite crystalline form with the c-axis parallel to the growth direction.…”

mentioning

confidence: 99%

Characteristics of AlN/GaN nanowire Bragg mirror grown on (001) silicon by molecular beam epitaxy

Heo

Zhou

Guo

et al. 2013

Applied Physics Letters

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“…Electron beam evaporation is used for evaporating the ohmic p-metal contact containing nickel and gold metals of thicknesses 30 and 150 nm respectively. The thicknesses of the metals were previously optimized to behave like an ohmic metal contact with p-type GaN material [68]. The sample with evaporated metal is left in an acetone bath to facilitate the lift-off procedure and expose the contact on the sample as shown in the Figure 5.5.…”

Section: Figure 54 Photolithography Process For Metal Contact Pattermentioning

confidence: 99%

“…With the precise control of the epitaxial growth and fabrication methods, the device-level characteristics (shown in the Figure 1.4 b.) are optimized for repeatable and stable devices[26],[27].…”

mentioning

confidence: 99%

Design, Fabrication and Characterization of Photonic Crystal Light-Emitting Diodes for Solid-State Lighting

Kadiyala¹

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Residential, commercial, and industrial lighting applications contribute to ~19% of total energy consumption worldwide. The application of more efficient sources of lighting, such as solid-state lighting (SSL) sources, could result in potential energy savings of about 65%. Current technologies employ semiconductor-based light-emitting diodes (LEDs) as the core elements of SSL devices to provide generalpurpose light in a wide range of color temperatures. However, there still exists several device level issues, such as poor material quality, low quantum efficiencies, large percentage of light being trapped, etc. These non-idealities are barriers for SSL sources replacing incandescent and compact fluorescent sources on an equivalent lumens-per-watt basis. WVU SSL research interests involve addressing device-level issues associated with III-V nitride materials, as well as optimizing the growth of materials and performance of fabricated devices. One major goal of research efforts is to provide solutions for improvement in light extraction in III-nitride-based devices Dawson for his guidance towards my thesis work. Dr. Dawson's wisdom, patience and constant encouragement are some of the reasons that have made the findings in this thesis possible.

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Surfactant effects of indium on cracking in AlN/GaN distributed Bragg reflectors grown via metal organic vapor phase epitaxy

Cited by 9 publications

References 32 publications

Improvement in the Light Extraction of Blue InGaN/GaN-Based LEDs Using Patterned Metal Contacts

Improvement in the Light Extraction of Blue InGaN/GaN-Based LEDs Using Patterned Metal Contacts

Characteristics of AlN/GaN nanowire Bragg mirror grown on (001) silicon by molecular beam epitaxy

Design, Fabrication and Characterization of Photonic Crystal Light-Emitting Diodes for Solid-State Lighting

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