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Vol.46, No.10, 683 ~ 691, 2008
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| Title |
| Electron Beam Evaporated ITO Transparent Electrode for Highly Efficiency GaN-based Light Emitting Diode |
| 서재원 Jae Won Seo , 오화섭 Hwa Sub Oh , 강기만 Ki Man Kang , 문성민 Seong Min Moon , 곽준섭 Joon Seop Kwak , 이국회 Kuk Hwe Lee , 이우현 Woo Hyun Lee , 박영호 Young Ho Park , 박해성 Hae Sung Park |
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| Abstract |
| In order to develop transparent electrodes for high efficiency GaN-based light emitting diodes (LEDs), the electrical and optical properties of the electron beam evaporated ITO contacts have been investigated as a function of the deposition temperature and flow rate of oxygen during the deposition. As the deposition temperature increases from 140℃ to 220℃, the resistivity of the ITO films decreases slightly from 4.0×10-4 Ωcm to 3.3×10-4 Ωcm, meanwhile the transmittance of the ITO films significantly increases from 67% to 88% at the wavelength of 470 nm. When the flow rate of oxygen during the deposition increases from 2 sccm to 4 sccm, the resistivity of the ITO films increases from 3.6×10-4 Ωcm to 7.4×10-4 Ωcm, meanwhile the transmittance of the ITO films increases from 86% to 99% at 470 nm. Blue LEDs fabricated with the electron beam evaporated ITO electrode show that the ITO films deposited at 200℃ and 3 sccm of the oxygen flow rate give a low forward-bias voltage of 3.55 V at injection current of 20 mA with a highest output power. |
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| Key Words |
| ITO, ohmic contact, LED, electron beam evaporator |
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