신소재공학 GaN LED 투명 전극 실험(영문)

신소재공학 GaN LED 투명 전극 실험(영문)

[신소재공학] GaN LED 투명 전극 실험(영문).pptx

목차 1.Abstract 2.Introduction 3.Ag(5nm)/Graphene 4.Measuring Contact Resistance 5.Ni-patterned layer 6.Experiment 7.Conclusion 8.Future Work 본문 We investigated graphene-based transparent electrodes for InGaN/GaN light emitting diodes(LED). Nano-dotted layer of Ag and Ni were inserted between p-GaN and graphene to achieve low contact resistance and high transmittance. Heat treated Ag layer/graphene had low contact resistance of 0.7~1.2Ω/cm2, and we could achieve better luminance for GaN-based LED. However, for patterned Ni layer/graphene electrode, we failed to measure the contact resistance. Structure of GaN based LED : 'Top emission' and 'Vertical' structures Since achieving heavily doped p-GaN is difficult, it is hard for p-GaN in top emission LED to spread the current from the p-electrode, which results in low intensity of LED. Therefore, transparent ohmic contact to p-GaN with low resistance is essential for achieving GaN-based LED with better efficiency. Desired : Low contact resistance to p-GaN and High transmittance. ① Metal layer ☞ Low Contact Resistance, but Low transmittance ② Graphene layer☞ Excellent Transmittance, but High contact resistance ③ Metal/Graphene layer to p-GaN☞ Improved contact resistance, but not quite high transmittance. 키워드 GaN, contact, pGaN