噴墨製程與金屬氧化物在高分子發光二極體及DVD-R光碟中性質之研究

Investigation of inkjet printing process and properties of metal-oxide material in polymer light emitting diode and DVD-R optical disc

洪耀第(Yao-Ti, Hung)

指導教授 ： 劉宗平

元智大學/工程學院/電機工程學系/博士(2006年)

摘要

在金屬氧化物薄膜製備的過程中，會因反應氣體的種類與流量的因素而影響到薄膜的光電性質。本文主要探討利用金屬氧化物-氧化銦錫（indium tin oxide, ITO）來製作有機高分子二極體（polymer light emitting diode, PLED）元件中透明導電電極的光電性質。在直流磁控反應性濺鍍系統中，除了通入固定流量的氬氣之外，還通入不同流量的氧氣與氫氣作為反應氣體，探討不同氫氣流量對ITO膜的光學、電學、表面形貌及結構等特性之影響。此外，當ITO膜經不同的表面處理條件，以及不同真空度條件下蒸鍍製作陰極金屬鈣時，對PLED元件效率的影響。

實驗結果顯示，當氫氣與氧氣流量相同為25 sccm時，ITO膜有最低的電阻率。從表面形貌的觀測可知，在氧氣與氫氣流量同為25 sccm下所沉積的ITO薄膜，其有低的表面粗度值及較少的晶界數目，致使其載子遷移率降低；這就是降低載子散射機制的緣由。同時，由PLED元件的電性量測結果顯示，當使用CF4/O2混合氣體的比例為30時，元件有較高的電流密度與亮度，論文中用來製作全彩的 PLED顯示器所使用的熱汽泡式噴印頭，其係由工研院所研發。並且，由PLED元件的I-V、 L-V、以及交流阻抗量測的結果可知，蒸鍍鈣時的真空度若從4×10-4 Pa增加到6.6×10-4 Pa時，有低的注入電流密度與亮度。亦即，在不同真空度下，在PF與鈣之間的界面，所產生氧化鈣的量，會受到真空腔體內殘留氧氣的影響。

同時，本論文也將探討熱汽泡式噴印頭與高分子溶液間的相容性測試。由實驗結果顯示，高分子發光材料本身若有適當的耐熱性，則可以使用熱汽泡式的噴嘴頭來製作PLED顯示器的發光層薄膜。在相容性試驗之後，除了ITO的表面處理與陰極金屬鈣蒸鍍時的真空度等條件外，還探討不同的polyflouorene（PF）退火溫度對PLED元件的效率影響。由電性量測結果顯示，退火溫度為140 OC時有較高的注入電流密度。

最後，來探討利用交流磁控反應性濺鍍程序所製作氧化鉻膜的性質，以其作為DVD-R光碟中新的記錄層材料。在氧氣流量為40 sccm的條件下，利用鍍膜技術製作結構為[PC/ZnS-SiO2 (30 nm)/CrOx (120 nm)/ZnS-SiO2 (40 nm)/Ag (50 nm)]的DVD-R碟片，它擁有較高的carrier-to-noise ratio (CNR)。

關鍵字

氧化銦錫；有機高分子二極體；熱汽泡式噴印頭；氧化鉻；DVD-R光碟

並列摘要

In the metal-oxide thin film deposited process, the reactive gas and their flow rate will influence metal-oxide thin film of optoelectronic properties. Belong metal-oxide of indium tin oxide（ITO）had been usually used to fabricated the transparent conducting electrode of polymer light emitting diode（PLED）device of. The effect H2-O2-Ar mixture gas of flow rate on optoelectronic properties and structural of the ITO film deposited by dc reactive magnetron sputtering technique was investigated in this thesis. Meanwhile, effects of different ITO surface treatment processing, vacuum degree during the cathode calcium evaporation on the efficiency of a PLED device were also investigated.

The experimental has been demonstrated that there was the lowest resistivity can obtained as the flows of H2 and O2 were both 25 sccm. From Hall measurement, although the carrier concentration was not the maximum, the highest carrier mobility occurred. In observing the surface morphology, it is shown that the surface roughness is low and the number of grain boundary is small so that the carrier mobility is high as the flows of H2 and O2 were both 25 sccm. This is the reason to inhibit the scattering mechanism of carriers. Results from real inkjet printing, they showed that the use of the mixed gas of CF4/O2 with the ratio of 30 in a microwave plasma system was probable to be the surface treatment condition of ink-jet print for a full-color PLED display prepared by the thermal bubble inkjet print head developed by Industrial Technology Research Institute. Moreover, the results, by using I-V, L-V, and ac impedance, show that the luminescence and electrical properties of PLED can be significantly improved as the vacuum level increases from 6.6x10-4 to 4x10-4 Pa during Ca evaporation. This is that the quantity of calcium oxide generated at the interface between PF and calcium was affected by the residual oxygen in the chamber at different vacuum level.

In addition, a series of compatibility test for thermal bubble inkjet print head with each polymer solution was discussed. The result showed that it was able to make the thin film of the luminescence layer of a PLED display by using thermal bubble inkjet print head as the polymer luminescent material gave the appreciated heat resistance. After compatibility tests, in addition to effects of different ITO surface treatment processing and vacuum level during cathode calcium evaporation, the efficiency of PLED device affected by the various annealing temperature of PF were also investigated. From measurements, the device has the smaller impedance as polyflouorene (PF) annealed at 140 OC.

Finally, the properties of CrOx film deposited by RF magnetron reactive sputtering process was also investigated to use it as a new recording layer for recordable digital versatile disc (DVD-R) with a red laser. A DVD-R structure of PC/ZnS-SiO2(30 nm)/CrOx(120 nm)/ZnS-SiO2(40 nm)/Ag(50 nm), deposited by sputtering at O2 flow rate of 40 sccm, had an improved carrier-to-noise ratio (CNR).

並列關鍵字

indium tin oxide ； polymer light emitting diode ； thermal bubble inkjet print head ； CrOx ； DVD-R

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