Study of Aluminum-doped zinc oxide current spreading layer on P-side up thin-film AlGaInP-based light-emitting diodes by ALD

Ming Chun Tseng, Chi Lu Chen, Nan Kai Lai, Dong Sing Wuu, Hsin Ying Lee, Yu Chang Lin, Ray-Hua Horng

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations

Abstract

A twice wafer-transfer technique can be used to fabricate high-brightness p-side-up thin-film AlGaInP-based light-emitting diodes (LEDs) with an aluminum-doped zinc oxide (AZO) thin films transparent conductive layer deposited on a GaP window layer. The GaP window layer consist of the two different doping profile, the carbon doped Gap (GaP:C) window layer of 50 nm is on the top of Mg doped GaP window layer of 8 1/4m. The GaP:C window layer is used to improved the ohmic contact properties of GaP:C/AZO. The AZO with different cycle ratio of Zn:Al (15:1, 20:1 and 25:1) is deposited on GaP:C window layer as current spreading layer by atomic layer deposition. The AZO layer can be used to improve light extraction, which enhances light output power. The output power of p-side-up thin-film AlGaInP LED with an AZO layer of 20:1 cycle ratio has improved up to 19.2 % at injection current of 350 mA, as compared with that of LED without AZO film. The p-side-up thin-film AlGaInP LED with AZO current spreading layer exhibited excellent performance stability, the emission wavelength shift of p-side-up thin-film AlGaInP LED without and with AZO thin film(Zn:Al=20:1) are 17 nm and 3 nm under the injection current increased from 20 mA to 1000mA, respectively. This stability can be attributed to the following factors: 1) Refractive index matching, performed by introducing AZO thin film between the epoxy and the GaP window layer enhances light extraction; and 2) the favorable thermal dissipation of the silicon substrate reduces thermal degradation.

Original languageEnglish
Title of host publicationLight-Emitting Diodes
Subtitle of host publicationMaterials, Devices, and Applications for Solid State Lighting XIX
EditorsKlaus P. Streubel, Heonsu Jeon, Li-Wei Tu, Martin Strassburg
PublisherSPIE
ISBN (Electronic)9781628414738
DOIs
StatePublished - 1 Jan 2015
EventLight-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XIX - San Francisco, United States
Duration: 10 Feb 201512 Feb 2015

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume9383
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Conference

ConferenceLight-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XIX
CountryUnited States
CitySan Francisco
Period10/02/1512/02/15

Keywords

  • Current spreading layer
  • P-side up thin-film LED

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