| 摘要: | 本論文採用電子槍蒸鍍系統，蒸鍍透明導電薄膜GZO，探討薄膜光電特性與材料特性，以及在P型氮化鎵上歐姆接觸，最後應用在氮化鎵LED上與傳統薄膜ITO相互比較，探討其光電特性。 當Ga在薄膜GZO的含量約為6 At%時，薄膜電阻率可達最低值為2.44 ×10-4 ohm-cm。薄膜GZO與傳統薄膜ITO相比，薄膜電阻率同在1×10-4 ohm -cm 等級，在可見光波段皆具有90%的穿透率。 蒸鍍兩組不同電阻率的薄膜GZO在P型氮化鎵上與氮化鎵LED晶片上，與傳統之透明導電薄膜ITO相互比較，樣品P-1 = 6.31×10-4 ohm-cm和P-2 = 3.56×10-4 ohm -cm 分別為薄膜GZO在P型氮化鎵上的薄膜電阻率與樣品P-ITO = 1.73× 10-4 ohm -cm為薄膜ITO在P型氮化鎵上的薄膜電阻率，其特徵接觸電阻值為P-1 = 7.49×10-1 ohm-cm2、P-2 = 1.48×10-1 ohm-cm2和P-ITO = 2.61 ×10-2 ohm-cm2。在20mA電流注入下的操作電壓值，GZO LED -1= 3.89 V和GZO LED-2 = 3.47 V比ITO LED = 3.35 V分別高出約 0.54V和0.12V。在20mA電流注入下之光輸出功率值，GZO LED-1=2.02 mW和GZO LED-2= 1.98 mW比ITO LED = 1.7 mW分別約高出19%和16%，在20mA 電流注入下之外部量子效率值，GZO LED-1=3.63%和GZO LED-2 = 3.55%比ITO LED 3.06%分別約高出18.6%和16%。 另外，薄膜GZO在不同溫度熱處理後，薄膜的電阻率皆變大，且薄膜GZO在P型氮化鎵上的特徵接觸電阻值皆變大。在20mA 電流注入下，經不同溫度熱處理後之GZO LED其操作電壓皆變高，且在光輸出功率和外部量子效率值都變小。In this study, we adopt E-Gun evaporation system to deposit Gallium doped Zinc Oxide (GZO). We analyze the optical and electrical properties of GZO thin film and also discuss the contact property on p-GaN. Finally, we compare the electrical and optical characteristics of GZO TCL LEDs with conventional ITO TCL LEDs. At the Ga content of 6At.%, we obtained the lowest resistivity (ρ) was 2.44×10-4 ohm-cm which was at the same order of ITO thin film (1×10-4 ohm-cm) and the transmittance was the above 90% at visible range which was comparable with ITO thin film. We prepared two as-deposited GZO films on p-GaN and LEDs of different resistivities, 6.31×10-4 ohm-cm (P-1) and 3.56×10-4 ohm-cm (P-2), to study the electrical contact property and compared with ITO film with resistivity of 1.73×10-4 ohm-cm (P-ITO). The specific contact resistances (ρc) of P-1, P-2 and P-ITO were 7.49×10-1 ohm-cm2, 1.48×10-1 ohm-cm2 and 2.61 ×10-2 ohm-cm2, respectively. After the chip process, we characterized the electrical and optical properties of GZO-LEDs and ITO-LEDs at the injection current of 20mA. The forward voltage of GZO LED-1, GZO LED-1 and ITO-LED were 3.89 V, 3.47 V and 3.35 V, respectively. The forward voltage of GZO-LEDs exhibited 0.54V and 0.12V higher than that of ITO-LED. The output powers were 2.02mW, 1.98mW, and 1.7mW for GZO LED-1, GZO LED-2 and ITO LED, respectively. The output powers were enhanced by 19% and 16% for GZO LED-1, GZO LED-2 compared with that of ITO-LED. On the other hand, the external quantum efficiency were 3.63% and 3.55% for GZO LED-1, GZO LED-2 which showed 18.6% and 16% enhancement compared with that of ITO-LED,3.06%. We also did annealing process for GZO films and then did the chip process. However, we found that? ρ and ρc would be deteriorated after annealing process. At 20mA injection current, the forward voltages were higher than those as-deposit and degradations of EQE and output powers were also observed. |
