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Enhanced performance of photonic crystal GaN light-emitting diodes with graphene transparent electrodes.

Ge HL, Xu C, Xu K, Xun M, Wang J, Liu J - Nanoscale Res Lett (2015)

Bottom Line: Specially, we found that the part of the graphene suspending over the air hole of the PC structure was of much higher conductivity, which reduced the average sheet resistance of the graphene transparent conducting electrode and improved the current spreading of the PC LED.Therefore, the work voltage of the DGTE-PC LED was obviously decreased, and the output power was greatly enhanced.The results show that the etching of PC structure results in the degradation of the current spreading and that the graphene transparent conducting electrode can offer an uniform current spreading in the DGTE-PC LED. 85.60.Jb; 68.65.Pq; 42.70.Qs.

View Article: PubMed Central - PubMed

Affiliation: The Key Laboratory of Optoelectronics Technology, Ministry of Education, Beijing University of Technology, Beijing, 100124 People's Republic of China.

ABSTRACT

Unlabelled: The two-dimensional (2D) triangle lattice air hole photonic crystal (PC) GaN-based light-emitting diodes (LED) with double-layer graphene transparent electrodes (DGTE) have been produced. The current spreading effect of the double-layer graphene (GR) on the surface of the PC structure of the LED has been researched. Specially, we found that the part of the graphene suspending over the air hole of the PC structure was of much higher conductivity, which reduced the average sheet resistance of the graphene transparent conducting electrode and improved the current spreading of the PC LED. Therefore, the work voltage of the DGTE-PC LED was obviously decreased, and the output power was greatly enhanced. The COMSOL software was used to simulate the current density distribution of the samples. The results show that the etching of PC structure results in the degradation of the current spreading and that the graphene transparent conducting electrode can offer an uniform current spreading in the DGTE-PC LED.

Pacs: 85.60.Jb; 68.65.Pq; 42.70.Qs.

No MeSH data available.


The image of the normalized current density along the E-F line. A The normalized current density of the LED with the graphene electrode of 150 Ω/□; B that of the LED with the graphene electrode of 300 Ω/□; C that of the PC LED without graphene electrode; D that of the conventional LED without graphene.
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Fig8: The image of the normalized current density along the E-F line. A The normalized current density of the LED with the graphene electrode of 150 Ω/□; B that of the LED with the graphene electrode of 300 Ω/□; C that of the PC LED without graphene electrode; D that of the conventional LED without graphene.

Mentions: To quantitatively describe the impact of graphene on the current spreading, the COMSOL software was used to simulate the current density distribution on the surface of the MQWs layer of the samples. We choose the current density along the typical E-F line (as shown in Figure 1) at the injection current of I = 20 mA, shown in Figure 8. We can find that the current spreading of the B0# sample is seriously degraded, compare with that of the A0# sample, showing the current spreading degradation due to the etching of PC structure. The current spreading of the LED is improved obviously when the graphene electrode is used. The curve of the current density of the LED with the graphene electrode of 150 Ω/□ is more flat, showing better current spreading than that of the LED with the graphene electrode of 300 Ω/□. The lower the sheet resistance of the graphene is, the better the current spreading is. Obviously, the suspended graphene over the air hole is beneficial for the current spreading. The tail of the curve may be caused by the agglomeration effect of the current. It can be seen that the simulation results and experimental results are consistent.Figure 8


Enhanced performance of photonic crystal GaN light-emitting diodes with graphene transparent electrodes.

Ge HL, Xu C, Xu K, Xun M, Wang J, Liu J - Nanoscale Res Lett (2015)

The image of the normalized current density along the E-F line. A The normalized current density of the LED with the graphene electrode of 150 Ω/□; B that of the LED with the graphene electrode of 300 Ω/□; C that of the PC LED without graphene electrode; D that of the conventional LED without graphene.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4385276&req=5

Fig8: The image of the normalized current density along the E-F line. A The normalized current density of the LED with the graphene electrode of 150 Ω/□; B that of the LED with the graphene electrode of 300 Ω/□; C that of the PC LED without graphene electrode; D that of the conventional LED without graphene.
Mentions: To quantitatively describe the impact of graphene on the current spreading, the COMSOL software was used to simulate the current density distribution on the surface of the MQWs layer of the samples. We choose the current density along the typical E-F line (as shown in Figure 1) at the injection current of I = 20 mA, shown in Figure 8. We can find that the current spreading of the B0# sample is seriously degraded, compare with that of the A0# sample, showing the current spreading degradation due to the etching of PC structure. The current spreading of the LED is improved obviously when the graphene electrode is used. The curve of the current density of the LED with the graphene electrode of 150 Ω/□ is more flat, showing better current spreading than that of the LED with the graphene electrode of 300 Ω/□. The lower the sheet resistance of the graphene is, the better the current spreading is. Obviously, the suspended graphene over the air hole is beneficial for the current spreading. The tail of the curve may be caused by the agglomeration effect of the current. It can be seen that the simulation results and experimental results are consistent.Figure 8

Bottom Line: Specially, we found that the part of the graphene suspending over the air hole of the PC structure was of much higher conductivity, which reduced the average sheet resistance of the graphene transparent conducting electrode and improved the current spreading of the PC LED.Therefore, the work voltage of the DGTE-PC LED was obviously decreased, and the output power was greatly enhanced.The results show that the etching of PC structure results in the degradation of the current spreading and that the graphene transparent conducting electrode can offer an uniform current spreading in the DGTE-PC LED. 85.60.Jb; 68.65.Pq; 42.70.Qs.

View Article: PubMed Central - PubMed

Affiliation: The Key Laboratory of Optoelectronics Technology, Ministry of Education, Beijing University of Technology, Beijing, 100124 People's Republic of China.

ABSTRACT

Unlabelled: The two-dimensional (2D) triangle lattice air hole photonic crystal (PC) GaN-based light-emitting diodes (LED) with double-layer graphene transparent electrodes (DGTE) have been produced. The current spreading effect of the double-layer graphene (GR) on the surface of the PC structure of the LED has been researched. Specially, we found that the part of the graphene suspending over the air hole of the PC structure was of much higher conductivity, which reduced the average sheet resistance of the graphene transparent conducting electrode and improved the current spreading of the PC LED. Therefore, the work voltage of the DGTE-PC LED was obviously decreased, and the output power was greatly enhanced. The COMSOL software was used to simulate the current density distribution of the samples. The results show that the etching of PC structure results in the degradation of the current spreading and that the graphene transparent conducting electrode can offer an uniform current spreading in the DGTE-PC LED.

Pacs: 85.60.Jb; 68.65.Pq; 42.70.Qs.

No MeSH data available.