In
                Ga
                N
                ∕
                Ga
                N
           light emitting diodes on nanoscale silicon on insulator

Tripathy, S.; Lin, Vivian Kaixin; Teo, Siew Lang; Dadgar, A.; Diez, A.; Bläsing, J.; Krost, A.

doi:10.1063/1.2814062

Cited by 37 publications

(14 citation statements)

References 37 publications

(30 reference statements)

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“…However, both sapphire and SiC are difficult to manufacture. In recent years, high quality a GaN-on-silicon system has been developed by using an intermediate buffer layer to reduce the crack density [3][4][5][6]. Additionally, bulk silicon micromachining is a mature technique.…”

Section: Introductionmentioning

confidence: 99%

Fabrication and characterization of subwavelength nanostructures on freestanding GaN slab

Wang¹,

Hu²,

Kanamori³

et al. 2010

Opt. Express

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We develop a novel way to fabricate subwavelength nanostructures on the freestanding GaN slab using a GaN-on-silicon system by combining self-assemble technique and backside thinning method. Silicon substrate beneath the GaN slab is removed by bulk silicon micromachining, generating the freestanding GaN slab and eliminating silicon absorption of the emitted light. Fast atom beam (FAB) etching is conducted to thin the freestanding GaN slab from the backside, reducing the number of confined modes inside the GaN slab. With self-assembled silica nanospheres acting as an etching mask, subwavelength nanostructures are realized on the GaN surface by FAB etching. The reflection losses at the GaN interfaces are thus suppressed. When the InGaN/GaN multiple quantum wells (MQWs) active layers are excited, the light extraction efficiency is significantly improved for the freestanding nanostructured GaN slab. This work provides a very practical approach to fabricate freestanding nanostructures on the GaN-on-silicon system for further improving the light extraction efficiency.

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Section: Introductionmentioning

confidence: 99%

Fabrication and characterization of subwavelength nanostructures on freestanding GaN slab

Wang¹,

Hu²,

Kanamori³

et al. 2010

Opt. Express

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“…This demands additional processing steps and difficulties while transferring large area GaN. Recently, we have explored an alternate solution by switching the epitaxy to large area silicon-oninsulator (SOI) substrates for nitride devices [7,8]. The absorption of visible light from LEDs will be much lower on very thin SOI due to a large dielectric contrast at the Si/SiO 2 /Si substrate-interfaces, which leads to strong EL intensity modulation.…”

mentioning

confidence: 99%

Light extraction from GaN‐based LED structures on silicon‐on‐insulator substrates

Tripathy

Teo

Lin

et al. 2010

Phys. Status Solidi (c)

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Nano‐patterning of GaN‐based devices is a promising technology in the development of high output power devices. Recent researches have been focused on the realization of two‐dimensional (2D) photonic crystal (PhC) structure to improve light extraction efficiency and to control the direction of emission. In this study, we have demonstrated improved light extraction from green light emitting diode (LED) structures on thin silicon‐on‐insulator (SOI) substrates using surface nanopatterning. Scanning electron microscopy (SEM) is used to probe the size, shape, and etch depth of nano‐patterns on the LED surfaces. Different types of nanopatterns were created by e‐beam lithography and inductively coupled plasma etching. The LED structures after post processing are studied by photoluminescence (PL) measurements. The GaN nanophotonic structures formed by ICP etching led to more than five‐fold increase in the intensity of the green emission. The improved light extraction is due to the combination of SOI substrate reflectivity and photonic structures on top GaN LED surfaces. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…An alternate solution is to grow LED structures on a large-area, thin reflective Si-on-insulator ͑SOI͒ substrates. 6,7 Recently, majority of research groups have been exploring two-dimensional ͑2D͒ photonic crystal ͑PhC͒ structures to improve the light-extraction efficiency ͑LEE͒ for high brightness LEDs. [8][9][10][11][12][13][14][15] In this study, we have carried out surface nanopatterning to enhance light emission from GaN-based LEDs on large-area silicon-based substrates.…”

mentioning

confidence: 99%

Luminescence Properties of Photonic Crystal InGaN/GaN Light Emitting Layers on Silicon-on-Insulator

Lin

Tripathy

Teo

et al. 2010

Electrochem. Solid-State Lett.

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The photonic crystal InGaN/GaN light emitting diodes ͑LEDs͒ on thin silicon-on-insulator ͑SOI͒ substrates are demonstrated. Surface nanopatterning has been carried out on such LED layers and the processing conditions are varied to improve the outcoupling of visible emission. A substantial increase in the photoluminescence intensity is observed from LEDs on a thin SOI overlayer as compared to a similar structure grown on a thicker SOI. In addition, enhancement of the cathodoluminescence and electroluminescence intensity from such photonic crystal LEDs shows their potential in solid-state lighting.According to the present solid-state lighting research, the luminescence efficiency of InGaN/GaN light emitting diodes ͑LEDs͒ can reach 80%. 1 Major LED manufacturing companies now focus on the development of high power and high brightness devices with suitable packaging for general illumination market. 1-3 An alternate low cost solution for street lighting and general illumination for GaN LEDs could be the use of large-area Si-based substrates. 4,5 One of the major concerns for the LEDs on Si substrate is the absorption of blue-green light emitted from InGaN/GaN multiquantum well ͑MQW͒ active layers. In this context, substrate removal is a necessary step to realize high brightness LEDs. An alternate solution is to grow LED structures on a large-area, thin reflective Si-on-insulator ͑SOI͒ substrates. 6,7 Recently, majority of research groups have been exploring two-dimensional ͑2D͒ photonic crystal ͑PhC͒ structures to improve the light-extraction efficiency ͑LEE͒ for high brightness LEDs. [8][9][10][11][12][13][14][15] In this study, we have carried out surface nanopatterning to enhance light emission from GaN-based LEDs on large-area silicon-based substrates. The LEDs with photonic nanostructures on thin SOI show substantial photoluminescence ͑PL͒, cathodoluminescence ͑CL͒, and electroluminescence ͑EL͒ intensity enhancement.The InGaN/GaN LEDs were grown by metallorganic chemical vapor deposition on SOI͑111͒ substrates with SOI overlayer thickness in the range of 45 to 200 nm with a buried oxide ͑BOX͒ thickness ranging from 150 to 375 nm. The full LED structure consisted of a high temperature buffer layer, an Al-rich intermediate layer, a 2.75 m n-type thick Si-doped GaN, five periods of InGaN/ GaN MQWs, and a 120 nm Mg-doped p-type GaN layer. For the light extraction study, we used two sets of LED samples, where layers were grown on thin SOI ͑45-50 nm overlayer with 150 nm BOX: green emission ϳ525 nm͒ and thick SOI ͑200 nm overlayer with 375 nm BOX: emission ϳ485 to 490 nm͒ substrates. The fabrication of 2D PhC structures on the LED surfaces was carried out by electron-beam lithography and dry etching of GaN using a SiO 2 nanomask. 7 The microscopic PL and EL spectra were recorded from the PhC structures using a Jobin Yvon LABRAM setup equipped with 325 nm excitation from a He-Cd laser. The low temperature CL measurements were carried out in a JEOL scanning electron microscope ͑SEM͒ equipped with a helium cryostat. To de...

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In Ga N ∕ Ga N light emitting diodes on nanoscale silicon on insulator

Cited by 37 publications

References 37 publications

Fabrication and characterization of subwavelength nanostructures on freestanding GaN slab

Fabrication and characterization of subwavelength nanostructures on freestanding GaN slab

Light extraction from GaN‐based LED structures on silicon‐on‐insulator substrates

Luminescence Properties of Photonic Crystal InGaN/GaN Light Emitting Layers on Silicon-on-Insulator

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