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 Metallayer
☞ Low Contact Resistance, but Low transmittance
② Graphene layer☞ Excellent Transmittance, but High contact resistance
③ Metal/Graphene layer to p-GaN☞ Improved contact resi
어떻게?
① Metal을 이용
☞ Contact Resistance ↓, but Transmittance ↓
② Graphene을 이용
☞ Transmittance ↑, but Contact Resistance ↑
③ Metal/Graphene layer를 이용
☞ Transmittance ↑, Contact Resistance ↓
④ Patterned metal + Graphene을 이용 !! ↕:Good
☞ Transmittance ↑↑, Contact Resistance ↓↓ ↕: Bad
2.3. Back contact
후면전극 물질로는 Sputtering법으로 증착된 Mo이 가장 광범위하게 사용된다. 이는 Mo이 가진 높은 전기전도도, CIGS와의 ohmic contact, Se 분위기 하에서의 고온 안정성 때문이다. Mo 박막은 전극으로서 비저항이 낮아야 하고 또한 열팽창계수의 차이로 인하여 박리현상이 일어나지 않도록
layer. When the charges exist in between the substrate and interface, the value of Vfb and C-V curve will shift by amount of the charge divided by Cox of Ci. The amount of shifting decreases as the position of fiexed charges is far from interface on the substrate and shifting will not exist any more when it is located on the interface between metal and interface. Mobile charges has the same effec
layer that may have built up. The last step removes any ionic or heavy metal contaminants.
The RCA clean procedure should be performed immediately prior to any crucial step, especially those involving high temperatures. For safety reasons, all activities in the RCA clean procedure should be performed in a Clean Station Work Area which is located under an exhaust fume hood.