Abstract
Based on the proposed experimental method, the current spreading length of GaN-based light-emitting diodes (LEDs) was measured and analyzed for practical device design. In this study, Thompson's and Guo's models, which are categorized according to vertical series resistance (in particular, p-type contact resistance), were used to extract device parameters. It was shown that the measured current spreading length strongly depends on the injected current density. For LEDs fabricated with low-resistance p-type contacts, this behavior could be explained in terms of the accelerated current crowding with higher current densities occurring as a result of the reduced voltage drop across the junction, which is in good agreement with Thompson's relation. However, for LEDs fabricated with high-resistance p-contacts, unlike Guo's prediction, the measured current spreading length also showed a strong dependence on the injected current density. This was attributed to thermal heating at the p-contact, resulting in the reduction of the voltage drop across the p-contact and so junction voltage, which is also in agreement with Thompson's model. Based on the measured parameters and the design rule, efficient p-type reflectors, namely, hybrid reflectors were designed. Compared with conventional ones, LEDs fabricated with the hybrid reflectors exhibited better output power at a reasonable forward voltage, indicating that the proposed method is effective in understanding the actual current spreading and hence the practical design of high-efficiency LEDs.
| Original language | English |
|---|---|
| Pages (from-to) | 625-632 |
| Number of pages | 8 |
| Journal | IEEE Journal of Quantum Electronics |
| Volume | 43 |
| Issue number | 8 |
| DOIs | |
| Publication status | Published - 2007 Aug 1 |
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Keywords
- Current crowding
- Design
- GaN
- Light-emitting diode (LED)
- Reflector
ASJC Scopus subject areas
- Electrical and Electronic Engineering
- Physics and Astronomy (miscellaneous)
Cite this
Consideration of the actual current-spreading length of gaN-based light-emitting diodes for high-efficiency design. / Kim, Hyunsoo; Cho, Jaehee; Lee, Jeong Wook; Yoon, Sukho; Kim, Hyungkun; Sone, Cheolsoo; Park, Yongjo; Seong, Tae Yeon.
In: IEEE Journal of Quantum Electronics, Vol. 43, No. 8, 01.08.2007, p. 625-632.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Consideration of the actual current-spreading length of gaN-based light-emitting diodes for high-efficiency design
AU - Kim, Hyunsoo
AU - Cho, Jaehee
AU - Lee, Jeong Wook
AU - Yoon, Sukho
AU - Kim, Hyungkun
AU - Sone, Cheolsoo
AU - Park, Yongjo
AU - Seong, Tae Yeon
PY - 2007/8/1
Y1 - 2007/8/1
N2 - Based on the proposed experimental method, the current spreading length of GaN-based light-emitting diodes (LEDs) was measured and analyzed for practical device design. In this study, Thompson's and Guo's models, which are categorized according to vertical series resistance (in particular, p-type contact resistance), were used to extract device parameters. It was shown that the measured current spreading length strongly depends on the injected current density. For LEDs fabricated with low-resistance p-type contacts, this behavior could be explained in terms of the accelerated current crowding with higher current densities occurring as a result of the reduced voltage drop across the junction, which is in good agreement with Thompson's relation. However, for LEDs fabricated with high-resistance p-contacts, unlike Guo's prediction, the measured current spreading length also showed a strong dependence on the injected current density. This was attributed to thermal heating at the p-contact, resulting in the reduction of the voltage drop across the p-contact and so junction voltage, which is also in agreement with Thompson's model. Based on the measured parameters and the design rule, efficient p-type reflectors, namely, hybrid reflectors were designed. Compared with conventional ones, LEDs fabricated with the hybrid reflectors exhibited better output power at a reasonable forward voltage, indicating that the proposed method is effective in understanding the actual current spreading and hence the practical design of high-efficiency LEDs.
AB - Based on the proposed experimental method, the current spreading length of GaN-based light-emitting diodes (LEDs) was measured and analyzed for practical device design. In this study, Thompson's and Guo's models, which are categorized according to vertical series resistance (in particular, p-type contact resistance), were used to extract device parameters. It was shown that the measured current spreading length strongly depends on the injected current density. For LEDs fabricated with low-resistance p-type contacts, this behavior could be explained in terms of the accelerated current crowding with higher current densities occurring as a result of the reduced voltage drop across the junction, which is in good agreement with Thompson's relation. However, for LEDs fabricated with high-resistance p-contacts, unlike Guo's prediction, the measured current spreading length also showed a strong dependence on the injected current density. This was attributed to thermal heating at the p-contact, resulting in the reduction of the voltage drop across the p-contact and so junction voltage, which is also in agreement with Thompson's model. Based on the measured parameters and the design rule, efficient p-type reflectors, namely, hybrid reflectors were designed. Compared with conventional ones, LEDs fabricated with the hybrid reflectors exhibited better output power at a reasonable forward voltage, indicating that the proposed method is effective in understanding the actual current spreading and hence the practical design of high-efficiency LEDs.
KW - Current crowding
KW - Design
KW - GaN
KW - Light-emitting diode (LED)
KW - Reflector
UR - http://www.scopus.com/inward/record.url?scp=34547129822&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=34547129822&partnerID=8YFLogxK
U2 - 10.1109/JQE.2007.900262
DO - 10.1109/JQE.2007.900262
M3 - Article
AN - SCOPUS:34547129822
VL - 43
SP - 625
EP - 632
JO - IEEE Journal of Quantum Electronics
JF - IEEE Journal of Quantum Electronics
SN - 0018-9197
IS - 8
ER -