TY - JOUR
T1 - Study of GaN-Based Light-Emitting Diode (LED) with a Hybrid Surface Structure
AU - Chen, Wei Cheng
AU - Niu, Jing Shiuan
AU - Liu, I. Ping
AU - Lee, Yu Lin
AU - Cheng, Shiou Ying
AU - Guo, Der Feng
AU - Liu, Wen Chau
N1 - Funding Information:
Manuscript received July 16, 2020; revised September 2, 2020; accepted September 10, 2020. Date of publication October 6, 2020; date of current version October 22, 2020. This work was supported in part by the Ministry of Science and Technology under Contract MOST 109-2221-E-006-083-MY2. The review of this article was arranged by Editor J. D. Phillips. (Corresponding authors: Der-Feng Guo; Wen-Chau Liu.) Wei-Cheng Chen, Jing-Shiuan Niu, Yu-Lin Lee, and Wen-Chau Liu are with the Department of Electrical Engineering, Institute of Microelectronics, National Cheng Kung University, Tainan 70101, Taiwan (e-mail: [email protected]).
Publisher Copyright:
© 1963-2012 IEEE.
PY - 2020/11
Y1 - 2020/11
N2 - A hybrid surface structure, incorporating an Ag-grid-based aluminum-doped zinc oxide (AZO) transparent conductive layer (TCL), a microhole array, 45°-sawtooth sidewalls, and an SiO2 nanoparticle (NP)/microsphere (MS) passivation layer, is proposed for the characteristic improvement of GaN-based light-emitting diodes (LEDs). In order to optimize the contact behavior between the AZO and p-GaN layers, a 2-D Ag grid is applied on the contact interface. Because series resistance Rs is reduced by the conductive Ag-grid pattern, a lower forward voltage and a better current spreading ability are obtained. Compared with a conventional GaN LED with an injection current of 200 mA, the proposed device exhibits a forward voltage of 4.01 V, reduced from 4.34 V, and presents 33%, 34.4%, 45.4%, 33.1%, and 45.3% enhancements in the light output power (LOP), luminous flux, luminous efficacy, external quantum efficiency (EQE), and wall-plug efficiency (WPE), respectively. Moreover, a more effective current spreading in the light emission mapping image and a higher intensity in the far-field pattern are achieved. Improvements of both electrical and optical properties verify that the proposed device is promising for practical applications in solid-state lighting.
AB - A hybrid surface structure, incorporating an Ag-grid-based aluminum-doped zinc oxide (AZO) transparent conductive layer (TCL), a microhole array, 45°-sawtooth sidewalls, and an SiO2 nanoparticle (NP)/microsphere (MS) passivation layer, is proposed for the characteristic improvement of GaN-based light-emitting diodes (LEDs). In order to optimize the contact behavior between the AZO and p-GaN layers, a 2-D Ag grid is applied on the contact interface. Because series resistance Rs is reduced by the conductive Ag-grid pattern, a lower forward voltage and a better current spreading ability are obtained. Compared with a conventional GaN LED with an injection current of 200 mA, the proposed device exhibits a forward voltage of 4.01 V, reduced from 4.34 V, and presents 33%, 34.4%, 45.4%, 33.1%, and 45.3% enhancements in the light output power (LOP), luminous flux, luminous efficacy, external quantum efficiency (EQE), and wall-plug efficiency (WPE), respectively. Moreover, a more effective current spreading in the light emission mapping image and a higher intensity in the far-field pattern are achieved. Improvements of both electrical and optical properties verify that the proposed device is promising for practical applications in solid-state lighting.
UR - http://www.scopus.com/inward/record.url?scp=85095689266&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85095689266&partnerID=8YFLogxK
U2 - 10.1109/TED.2020.3025844
DO - 10.1109/TED.2020.3025844
M3 - Article
AN - SCOPUS:85095689266
SN - 0018-9383
VL - 67
SP - 4953
EP - 4957
JO - IEEE Transactions on Electron Devices
JF - IEEE Transactions on Electron Devices
IS - 11
M1 - 9214908
ER -