Increased Light Extraction of Thin-Film Flip-Chip UVB LEDs by Surface Texturing
Artikel i vetenskaplig tidskrift, 2023

Ultraviolet light-emitting diodes (LEDs) suffer from a low wall-plug efficiency, which is to a large extent limited by the poor light extraction efficiency (LEE). A thin-film flip-chip (TFFC) design with a roughened N-polar AlGaN surface can substantially improve this. We here demonstrate an enabling technology to realize TFFC LEDs emitting in the UVB range (280-320 nm), which includes standard LED processing in combination with electrochemical etching to remove the substrate. The integration of the electrochemical etching is achieved by epitaxial sacrificial and etch block layers in combination with encapsulation of the LED. The LEE was enhanced by around 25% when the N-polar AlGaN side of the TFFC LEDs was chemically roughened, reaching an external quantum efficiency of 2.25%. By further optimizing the surface structure, our ray-tracing simulations predict a higher LEE from the TFFC LEDs than flip-chip LEDs and a resulting higher wall-plug efficiency.

AlGaN

light-emitting diode

ultraviolet

surface texturing

electrochemical etching

light extraction

Författare

Michael Alexander Bergmann

Chalmers, Mikroteknologi och nanovetenskap, Fotonik

Johannes Enslin

Technische Universität Berlin

Martin Guttmann

Technische Universität Berlin

Luca Sulmoni

Technische Universität Berlin

Neysha Lobo Ploch

Ferdinand-Braun-Institut fur Hochstfrequenztechnik

Filip Hjort

Chalmers, Mikroteknologi och nanovetenskap, Fotonik

Tim Kolbe

Ferdinand-Braun-Institut fur Hochstfrequenztechnik

Tim Wernicke

Technische Universität Berlin

Michael Kneissl

Technische Universität Berlin

Ferdinand-Braun-Institut fur Hochstfrequenztechnik

Åsa Haglund

Chalmers, Mikroteknologi och nanovetenskap, Fotonik

ACS Photonics

2330-4022 (eISSN)

Vol. 10 2 368-373

Microcavity laser breakthrough for ultraviolet light (UV-LASE)

Europeiska kommissionen (EU) (EC/H2020/865622), 2020-08-01 -- 2025-07-31.

Ultravioletta och blå mikrokavitetslasrar

Vetenskapsrådet (VR) (2018-00295), 2019-01-01 -- 2024-12-31.

Ämneskategorier

Annan fysik

Nanoteknik

Den kondenserade materiens fysik

DOI

10.1021/acsphotonics.2c01352

PubMed

36820322

Mer information

Senast uppdaterat

2023-03-15