Abstract
Nitride-based ultraviolet light-emitting diodes (UV LEDs) are promising replacements for conventional UV lamps. However, the external quantum efficiency of UV LEDs is much lower than for visible LEDs due to light absorption in the p-GaN contact and electrode layers, along with p-AlGaN growth and doping issues. To minimize such absorption, we should obtain direct ohmic contact to p-AlGaN using UV-transparent ohmic electrodes and not use p-GaN as a contact layer. Here, we propose a glass-based transparent conductive electrode (TCE) produced using electrical breakdown (EBD) of an AlN thin film, and we apply the thin film to four (Al)GaN-based visible and UV LEDs with thin buffer layers for current spreading and damage protection. Compared to LEDs with optimal ITO contacts, our LEDs with AlN TCEs exhibit a lower forward voltage, higher light output power, and brighter light emission for all samples. The ohmic transport mechanism for current injection and spreading from the metal electrode to p-(Al)GaN layer via AlN TCE is also investigated by analyzing the p-(Al)GaN surface before and after EBD.
| Original language | English |
|---|---|
| Pages (from-to) | 35668-35677 |
| Number of pages | 10 |
| Journal | ACS Applied Materials and Interfaces |
| Volume | 8 |
| Issue number | 51 |
| DOIs | |
| Publication status | Published - 2016 Dec 28 |
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Keywords
- conducting filament
- light-emitting diode
- transparent conductive electrode
- ultraviolet
- wide-bandgap
ASJC Scopus subject areas
- Materials Science(all)
Cite this
Glass-Based Transparent Conductive Electrode : Its Application to Visible-to-Ultraviolet Light-Emitting Diodes. / Lee, Tae Ho; Kim, Kyeong Heon; Lee, Byeong Ryong; Park, Ju Hyun; Schubert, E. Fred; Kim, Tae Geun.
In: ACS Applied Materials and Interfaces, Vol. 8, No. 51, 28.12.2016, p. 35668-35677.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Glass-Based Transparent Conductive Electrode
T2 - Its Application to Visible-to-Ultraviolet Light-Emitting Diodes
AU - Lee, Tae Ho
AU - Kim, Kyeong Heon
AU - Lee, Byeong Ryong
AU - Park, Ju Hyun
AU - Schubert, E. Fred
AU - Kim, Tae Geun
PY - 2016/12/28
Y1 - 2016/12/28
N2 - Nitride-based ultraviolet light-emitting diodes (UV LEDs) are promising replacements for conventional UV lamps. However, the external quantum efficiency of UV LEDs is much lower than for visible LEDs due to light absorption in the p-GaN contact and electrode layers, along with p-AlGaN growth and doping issues. To minimize such absorption, we should obtain direct ohmic contact to p-AlGaN using UV-transparent ohmic electrodes and not use p-GaN as a contact layer. Here, we propose a glass-based transparent conductive electrode (TCE) produced using electrical breakdown (EBD) of an AlN thin film, and we apply the thin film to four (Al)GaN-based visible and UV LEDs with thin buffer layers for current spreading and damage protection. Compared to LEDs with optimal ITO contacts, our LEDs with AlN TCEs exhibit a lower forward voltage, higher light output power, and brighter light emission for all samples. The ohmic transport mechanism for current injection and spreading from the metal electrode to p-(Al)GaN layer via AlN TCE is also investigated by analyzing the p-(Al)GaN surface before and after EBD.
AB - Nitride-based ultraviolet light-emitting diodes (UV LEDs) are promising replacements for conventional UV lamps. However, the external quantum efficiency of UV LEDs is much lower than for visible LEDs due to light absorption in the p-GaN contact and electrode layers, along with p-AlGaN growth and doping issues. To minimize such absorption, we should obtain direct ohmic contact to p-AlGaN using UV-transparent ohmic electrodes and not use p-GaN as a contact layer. Here, we propose a glass-based transparent conductive electrode (TCE) produced using electrical breakdown (EBD) of an AlN thin film, and we apply the thin film to four (Al)GaN-based visible and UV LEDs with thin buffer layers for current spreading and damage protection. Compared to LEDs with optimal ITO contacts, our LEDs with AlN TCEs exhibit a lower forward voltage, higher light output power, and brighter light emission for all samples. The ohmic transport mechanism for current injection and spreading from the metal electrode to p-(Al)GaN layer via AlN TCE is also investigated by analyzing the p-(Al)GaN surface before and after EBD.
KW - conducting filament
KW - light-emitting diode
KW - transparent conductive electrode
KW - ultraviolet
KW - wide-bandgap
UR - http://www.scopus.com/inward/record.url?scp=85007564417&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85007564417&partnerID=8YFLogxK
U2 - 10.1021/acsami.6b12767
DO - 10.1021/acsami.6b12767
M3 - Article
VL - 8
SP - 35668
EP - 35677
JO - ACS applied materials & interfaces
JF - ACS applied materials & interfaces
SN - 1944-8244
IS - 51
ER -