Simulation on effect of metal/graphene hybrid transparent electrode on characteristics of GaN light emitting diodes

In order to decrease the Schottky barrier height and sheet resistance between graphene （Gr） and the p-GaN layers in GaN-based light-emitting diodes （LEDs）, some transparent thin films with good conductivity and large work function are essential to insert into Gr and p-GaN layers. In this work, the u...

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Published inChinese physics B Vol. 26; no. 10; pp. 283 - 288
Main Author 钱明灿 张淑芳 罗海军 龙兴明 吴芳 方亮 魏大鹏 孟凡明 胡宝山
Format Journal Article
LanguageEnglish
Published 01.10.2017
Subjects
GaN
发光二极管
混合
热特性
电极对
石墨
表面温度分布
金属
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ISSN1674-1056
2058-3834
DOI10.1088/1674-1056/26/10/104402

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Summary:In order to decrease the Schottky barrier height and sheet resistance between graphene （Gr） and the p-GaN layers in GaN-based light-emitting diodes （LEDs）, some transparent thin films with good conductivity and large work function are essential to insert into Gr and p-GaN layers. In this work, the ultra-thin films of four metals （silver （Ag）, golden （Au）, nickel （Ni）, platinum （Pt）） are explored to introduce as a bridge layer into Gr and p-GaN, respectively. The effect of a different combination of Gr/metal transparent conductive layers （TCLs） on the electrical, optical, and thermal characteristics of LED was investigated by the finite element methods. It is found that both the TCLs transmittance and the surface temperature of the LED chip reduces with the increase of the metal thickness, and the transmittance decreases to about 80% with the metal thickness increasing to 2 nm. The surface temperature distribution, operation voltage, and optical output power of the LED chips with different metal/Gr combination were calculated and analyzed. Based on the electrical, optical, and thermal performance of LEDs, it is found that 1.5-nm Ag or Ni or Pt, but 1-nm Au combined with 3 layered （L） Gr is the optimal Gr/metal hybrid transparent and current spreading electrode for ultra-violet （UV） or near-UV LEDs.
Bibliography:finite element methods, graphene, temperature distribution, transmittance, light-emitting diodes
Ming-Can Qian1, Shu-Fang Zhang2, Hai-Jun Luo1,3, Xing-Ming Long3, Fang Wul, Liang Fang1, Da-Peng Wei4, Fan-Ming Meng1, Bao-Shan Hu5（1 State Key Laboratory of Mechanical Transmission, College of Physics, Chongqing University, Chongqing 400044, China ;2 College of Software, Chongqing College of Electronic Engineering, Chongqing 401331, China ; 3 College of Physics and Electronic Engineering, Chongqing Normal University, Chongqing 400047, China ; 4 Chongqing Engineering Research Center of Graphene Film Manufacturing, Chongqing 401331, China ;5 College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 401331, China）
11-5639/O4
In order to decrease the Schottky barrier height and sheet resistance between graphene （Gr） and the p-GaN layers in GaN-based light-emitting diodes （LEDs）, some transparent thin films with good conductivity and large work function are essential to insert into Gr and p-GaN layers. In this work, the ultra-thin films of four metals （silver （Ag）, golden （Au）, nickel （Ni）, platinum （Pt）） are explored to introduce as a bridge layer into Gr and p-GaN, respectively. The effect of a different combination of Gr/metal transparent conductive layers （TCLs） on the electrical, optical, and thermal characteristics of LED was investigated by the finite element methods. It is found that both the TCLs transmittance and the surface temperature of the LED chip reduces with the increase of the metal thickness, and the transmittance decreases to about 80% with the metal thickness increasing to 2 nm. The surface temperature distribution, operation voltage, and optical output power of the LED chips with different metal/Gr combination were calculated and analyzed. Based on the electrical, optical, and thermal performance of LEDs, it is found that 1.5-nm Ag or Ni or Pt, but 1-nm Au combined with 3 layered （L） Gr is the optimal Gr/metal hybrid transparent and current spreading electrode for ultra-violet （UV） or near-UV LEDs.
ISSN:1674-1056
2058-3834
DOI:10.1088/1674-1056/26/10/104402