GaN-free transparent ultraviolet light-emitting diodes

Nishida, Toshio; Kobayashi, Naoki; Ban, Tomoyuki
January 2003
Applied Physics Letters;1/6/2003, Vol. 82 Issue 1, p1
Academic Journal
By introducing a GaN-free layer structure, we have transparent light-emitting diodes (LEDs) at the ultraviolet emission wavelength of 348-351 nm, which is shorter than the GaN band gap wavelength of 363 nm. The buffer layer consists of an AlGaN alloy directly grown on an AlN template layer on a sapphire substrate, and a short period alloy superlattice is adopted as p-type cladding and p-type contact layers. The transparency of the epitaxially grown layer structure is confirmed from transmission spectra. The output powers of the device are 1 mW at injection currents of 20 and 7 mW at 220 mA under room temperature continuous wave operation. The highest external quantum efficiency is 1.4%. This value is superior to that of an ultraviolet LED grown on a high-quality bulk-GaN substrate, where the performance was significantly deteriorated by light absorption into the GaN substrate. The results here indicate the importance of a transparent device structure free of GaN to improve the performance of ultraviolet LEDs in wavelength ranges shorter than 363 nm.


Related Articles

  • Submilliwatt operation of AlGaN-based ultraviolet light-emitting diode using short-period alloy superlattice. Nishida, T.; Saito, H.; Kobayashi, N. // Applied Physics Letters;1/22/2001, Vol. 78 Issue 4, p399 

    Over 0.1 mW ultraviolet output was achieved by an AlGaN-based light-emitting diode. To realize a highly conductive and ultraviolet-transparent layer, a short-period alloy superlattice was introduced. The device was fabricated on SiC substrate. Low electric resistivity due to the short-period...

  • Combinatorial fabrication and studies of intense efficient ultraviolet–violet organic light-emitting device arrays. Zou, L.; Savvate’ev, V.; Booher, J.; Kim, C.-H.; Shinar, J. // Applied Physics Letters;10/1/2001, Vol. 79 Issue 14, p2282 

    Arrays of ultraviolet–violet (indium tin oxide)/[copper phthalocyanine (CuPc)]/[4,4′-bis(9-carbazolyl)biphenyl (CBP)]/[2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4oxadiazole (Bu-PBD)]/CsF/Al organic light-emitting devices, fabricated combinatorially using a sliding shutter...

  • RadTech Forms New UV LED Group.  // Paint & Coatings Industry;Mar2013, Vol. 29 Issue 3, p8 

    The article reports on a committee formed by the RadTech association in Bethesda, Maryland in March 2013 to focus on ultraviolet (UV) light emitting diode (LED) technology.

  • Potential of UV LED Technology Featured at uv.eb EAST.  // Paint & Coatings Industry;Dec2013, Vol. 29 Issue 12, p11 

    The article discusses the uv.eb EAST Conference and Exhibition that was held in Syracuse, New York from October 1-2, 2013.

  • UV LEDs live long, so you prosper. Schweber, Bill // EDN Europe;Dec2002, Vol. 47 Issue 12, p15 

    Features the ultraviolet LED from the Optoelectronics Division of Bivar Inc. Specifications of the product; Price of the product; Contact information.

  • Semiconducting polymer diodes: Large size, low cost photodetectors with excellent.... Yu, G.; Pakbaz, K. // Applied Physics Letters;6/20/1994, Vol. 64 Issue 25, p3422 

    Examines the sensitivity of photodiodes fabricated from conjugated polymers to visible-ultraviolet (UV) radiation. Correlation of photosensitivity with reverse bias voltage; Photoresponse of diodes fabricated from poly(3-octyl thiopene) in the visible and near UV; Effect of the ease of...

  • The process and efficiency of ultraviolet generation from gallium nitride blue light emitting.... Basrur, J.P.; Choa, F.S. // Applied Physics Letters;9/8/1997, Vol. 71 Issue 10, p1385 

    Examines the process and efficiency of gallium nitride blue light emitting diodes. Aim in obtaining ultraviolet sources; Application of a four-level recombination model in the blue and ultraviolet (UV) light emission process; Influence of pump pulse amplitude and duration on the UV-to-blue...

  • Absorption measurements in dense cesium vapor using a UV-violet light-emitting diode. Ban, T.; Skenderović, H.; Ter-Avetisyan, S.; Pichler, G. // Applied Physics B: Lasers & Optics;2001, Vol. 72 Issue 3, p337 

    Abstract. We present results of absorption measurements in a dense superheated cesium vapor generated in an all-sapphire cell using a UV-violet light-emitting diode as a continuum source. Due to the very effective thermal destruction of Cs[sub 2] molecules, a number of diffuse and satellite...

  • Top-emission ultraviolet light-emitting diodes with peak emission at 280 nm. Yasan, A.; McClintock, R.; Mayes, K.; Darvish, S. R.; Kung, P.; Razeghi, M. // Applied Physics Letters;7/29/2002, Vol. 81 Issue 5, p801 

    We demonstrate light emission at 280 nm from UV light-emitting diodes consisting of AlInGaN/ AlInGaN multiple quantum wells. Turn-on voltage of the devices is ∼5 V with a differential resistance of ∼40 Ω. The peak emission wavelength redshifts ∼1 nm at high injection currents.


Read the Article


Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics