III-Nitride Short Period Superlattices for Deep UV Light Emitters

III-Nitride short period superlattices (SPSLs), whose period does not exceed ~2 nm (~8 monolayers), have a few unique properties allowing engineering of light-emitting devices emitting in deep UV range of wavelengths with significant reduction of dislocation density in the active layer. Such SPSLs can be grown using both molecular beam epitaxy and metal organic chemical vapor deposition approaches. Of the two growth methods, the former is discussed in more detail in this review. The electrical and optical properties of such SPSLs, as well as the design and fabrication of deep UV light-emitting devices based on these materials, are described and discussed.

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AlGaN-GaN UV light-emitting diodes grown on SiC by metal-organic chemical vapor deposition

IEEE Journal of Selected Topics in Quantum Electronics ◽

10.1109/2944.999184 ◽

2002 ◽

Vol 8 (2) ◽

pp. 298-301 ◽

Cited By ~ 10

Author(s):

Ting Gang Zhu ◽

J.C. Denyszyn ◽

U. Chowdhury ◽

M.M. Wong ◽

R.D. Dupuis

Keyword(s):

Chemical Vapor Deposition ◽

Vapor Deposition ◽

Light Emitting Diodes ◽

Uv Light ◽

Chemical Vapor ◽

Organic Chemical ◽

Light Emitting ◽

Metal Organic ◽

Organic Chemical Vapor Deposition

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Present Status of Deep UV Nitride Light Emitters

Materials Science Forum ◽

10.4028/www.scientific.net/msf.590.141 ◽

2008 ◽

Vol 590 ◽

pp. 141-174 ◽

Cited By ~ 3

Author(s):

Asif Khan ◽

Krishnan Balakrishnan

Keyword(s):

Uv Light ◽

Device Fabrication ◽

Material System ◽

Light Emitters ◽

Light Emitting ◽

Light Emitting Devices ◽

Technical Developments ◽

Deep Uv ◽

Ultraviolet Light Emitting Diodes ◽

High Aluminum

Ultraviolet light emitting diodes with emission wavelengths less than 400 nm have been developed using the AlInGaN material system. Rapid progress in material growth, device fabrication and packaging enabled demonstration of deep-UV light-emitting devices with emission from 400 to 210 nm with varying efficiencies. For high aluminum alloy compositions needed for the shorter wavelength devices, these materials border between having material properties like conventional semiconductors and insulators, adding a degree of complexity to developing efficient light emitting devices. This chapter provides a review of III-nitride based UV light emitting devices including technical developments that allow for emission in the ultraviolet spectrum, and an overview of their applications in optoelectronic systems.

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Short period p-type AlN/AlGaN superlattices for deep UV light emitters

MRS Proceedings ◽

10.1557/proc-1202-i10-03 ◽

2009 ◽

Vol 1202 ◽

Cited By ~ 2

Author(s):

Sergey A. Nikishin ◽

Boris Borisov ◽

Vladimir Mansurov ◽

Mahesh Pandikunta ◽

Indra Chary ◽

...

Keyword(s):

Ohmic Contacts ◽

Uv Light ◽

Hole Concentration ◽

Specific Contact Resistance ◽

Light Emitters ◽

Short Period ◽

Specific Contact ◽

Short Period Superlattices ◽

Deep Uv ◽

P Type

AbstractThe Mg doped AlN/AlxGa1-xN (0.03 ≤ x ≤ 0.05) short period superlattices (SPSLs) were grown by gas source molecular beam epitaxy on (0001) sapphire substrates. The average AlN mole fraction is ∼ 0.7 and the hole concentration is ∼ 7×1017 cm-3. Contacts formed to the SPSLs using Ni/Au bilayer are found to have specific contact resistance ∼ 5×10-5 Ωcm2 near room temperature and to show weak temperature dependence attributed to activation of Mg acceptors in the AlN barriers of SPSLs. These p-SPSLs are attractive for fabrication of transparent low resistive ohmic contacts for deep UV LEDs.

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Optical Properties of AlN/AlGa(In)N Short Period Superlattices – Deep UV Light Emitting Diodes

MRS Proceedings ◽

10.1557/proc-798-y1.9 ◽

2003 ◽

Vol 798 ◽

Cited By ~ 2

Author(s):

M. Holtz ◽

I. Ahmad ◽

V. V. Kuryatkov ◽

B. A. Borisov ◽

G. D. Kipshidze ◽

...

Keyword(s):

Optical Properties ◽

Buffer Layer ◽

Light Emitting Diodes ◽

Uv Light ◽

Effusion Cell ◽

Light Emitting ◽

Short Period ◽

Short Period Superlattices ◽

Deep Uv ◽

P Type

ABSTRACTWe report optical properties of deep UV light emitting diodes (LEDs). Devices are based on short period superlattices of AlN/AlxGa1-x(In)N (x ∼ 0.08) grown by gas source molecular beam epitaxy with ammonia. Structures consist of a 50-nm thick AlN nucleation/buffer layer deposited on sapphire. This is followed by a 1-micron thick Si-doped buffer layer of AlGaN or AlN/AlGa(In)N designed to be transparent for wavelengths longer than 240 nm. The design thickness of the superlattice well layers is systematically varied from 0.50 nm to 1.25 nm and the thickness of the barrier is varied from 0.75 nm to 2.00 nm. The n- and p-type SPSLs were doped with Si derived from silane and Mg evaporated from an effusion cell, respectively. We investigate device structures as well as superlattices which are nominally undoped, p-type, and n-type. Optical properties are investigated using reflectance, cathodoluminescence, and, in the case of LEDs, using electroluminescence. By controlling the properties of the superlattice, we obtain optical gaps ranging from 4.5 eV (276 nm) and 5.3 eV (234 nm). A systematic shift between the optical gap and the CL peak emission energy is discussed. Electrical properties are studied using I-V, C-V, and Hall effect. LEDs based on these superlattices and operating in the range of 260 to 280 nm exhibit turn-on voltages in the range of 4 to 6 V and support dc current densities in excess of 500 A/cm2 at room temperature. We present results on the electrical and optical properties of our LEDs designed using these studies.

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GaN-Based LEDs on Nano-Patterned Sapphire Substrates

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.415-417.656 ◽

2011 ◽

Vol 415-417 ◽

pp. 656-659

Author(s):

Jing Zhang ◽

Shiro Sakai

Keyword(s):

Nanoimprint Lithography ◽

Light Output ◽

Chemical Vapor ◽

Organic Chemical ◽

Light Emitting ◽

Light Emitting Devices ◽

Sapphire Substrates ◽

Metal Organic ◽

Organic Chemical Vapor Deposition ◽

Patterned Sapphire Substrates

We have successfully fabricated light emitting diodes (LEDs) based on patterned sapphire substrates (PSSs) fabricated by employing nanoimprint lithography (NIL) technique. The nano-patterns were designed as regular triangles consisting of columns, whose diameters and pitches were 100, 150, 200, 250 nm and 200, 300, 400, 500 nm, respectively. 412 nm wavelength LEDs grown by metal organic chemical vapor deposition (MOCVD) method were also demonstrated. The NIL technique and nano-etching by employing RIE were demonstrated in details. The qualities of all LEDs based on PSSs are superior compared with that non-patterned sapphire substrate LED. The experimental results showed that the light output power was increased by using the PSS structure. At a driving current of 20 mA, the light output powers of LEDs based on PSSs with 200, 300, 400 and 500 nm pitches are enhanced by 59%, 79%, 42% and 48%, compared with the conventional LEDs. These results provide promising potential to increase output powers of commercial light-emitting devices.

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Robust 285 nm Deep UV Light Emitting Diodes over Metal Organic Hydride Vapor Phase Epitaxially Grown AlN/Sapphire Templates

Japanese Journal of Applied Physics ◽

10.1143/jjap.46.l537 ◽

2007 ◽

Vol 46 (No. 23) ◽

pp. L537-L539 ◽

Cited By ~ 26

Author(s):

Vinod Adivarahan ◽

Qhalid Fareed ◽

Surendra Srivastava ◽

Thomas Katona ◽

Mikhail Gaevski ◽

...

Keyword(s):

Vapor Phase ◽

Light Emitting Diodes ◽

Uv Light ◽

Light Emitting ◽

Organic Hydride ◽

Metal Organic ◽

Deep Uv

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Electroluminescence of p-GaN/MgO/n-ZnO Heterojunction Light-emitting Diodes

MRS Proceedings ◽

10.1557/opl.2012.1466 ◽

2012 ◽

Vol 1439 ◽

pp. 109-114

Author(s):

XinYi Chen ◽

Alan M. C. Ng ◽

Aleksandra B. Djurišić ◽

Chi Chung Ling ◽

Wai-Kin Chan ◽

...

Keyword(s):

Light Emitting Diodes ◽

Zno Nanorods ◽

Emission Spectra ◽

Chemical Vapor ◽

Organic Chemical ◽

Light Emitting ◽

Type Layer ◽

Growth Properties ◽

Metal Organic ◽

Organic Chemical Vapor Deposition

ABSTRACTLight-emitting diodes (LEDs) based on p-GaN/ZnO heterojunction were fabricated. GaN was deposited on sapphire using metal-organic chemical vapor deposition (MOCVD), and two kinds of ZnO i.e. ZnO thin film deposited by sputtering and ZnO nanorods (NRs) grown by hydrothermal method were used as n-type layer respectively. MgO film with the thickness around 10 nm was deposited by electron-beam deposition to act as an interlayer between GaN and ZnO. Photoluminescence, electroluminescence and I-V curves were measured to compare the properties of GaN based heterojunction LEDs with different architectures. The existence of MgO interlayer as well as the morphology of ZnO obviously influenced the electrical and optical properties of GaN based LEDs. The effect of MgO interlayer on ZnO growth, properties and I-V curves and emission spectra of LEDs is discussed in detail.

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