| 摘要: | 本研究主要提出能於大氣環境中製備三氧化鉬(Molybdenum trioxide, MoO3 )薄膜之製程技術，以不同的熱處理方式使薄膜結晶化及產生不同形貌的微觀結構，探討熱處理後之材料性質及熱處理參數對材料形貌的影響和機制變化。最後將所製備之三氧化鉬薄膜作為電洞元件(Hole only device, HOD)之電洞注入層(Hole injection layer, HIL )，以測試其應用於半導體元件時之電洞注入增益效應，觀察膜厚度及結晶性質對元件特性的影響。除了提出熱處理方式外，本研究亦嘗試以AHM(Ammonium heptamolybdate tetrahydrate, (NH4)6Mo7O24 ·XH2O)水溶液及硝酸(Nitric acid, HNO3 )作為前驅溶液，並成功以旋轉塗佈方式製備出հ-MoO3的結晶薄膜。
本研究的第一部分以旋轉塗佈(Spin - coating )技術使前驅溶液沉積於基板上，用加熱平台進行熱處理，並對不同持溫時間的樣品進行檢測，包括: 元素分析(Elementary analysis)、表面形貌(Morphology analysis)、晶體結構(Crystalline analysis)與其光學特性，證實հ-MoO3 (Hexagonal phase)薄膜沉積於基板表面。沉積հ-MoO3薄膜於ITO玻璃表面的試片，於可見光波長(300 - 800 nm)範圍內穿透度能高達77 - 82%；應用於HOD中時，隨著MoO3厚度的增加及結晶性質的提升，與傳統的電洞傳輸層PEDOT:PSS相比，有更優越的效益。
本文的第二部分則以CO2 雷射之遠紅外線波長特有的熱效應，期望以更為迅速的方式提升薄膜的結晶性質。於SEM (Scannning electronic microscopy, SEM)下觀察吸收不同雷射能量後的樣品表面形貌，所得到的樣品具有針狀、片狀、塊狀等豐富的微觀形貌，並根據雷射功率及平台移動速度等參數探討其變化機制。
;This study aims at developing in-atmosphere methods for fabricating molybdenum trioxide (MoO3) thin films. The microstructures of the crystallized thin films by different heat treatment schemes were examined and the effects of various heat treatment approaches on crystallization mechanisms were studied. The fabricated molybdenum trioxide films were finally used as the hole injection layer (HIL) for an hole only device (HOD) to verify their effects on hole injection gain. The effects of film thickness and crystallinity on the characteristics of the device were investigated. In this study, we also propose to prepare the solution through incorporating AHM with nitric acid (HNO3) as the precursor solution. In result, we successfully fabricate h-MoO3 crystalline thin films by the spin coating scheme.
In the first part of this study, the precursor solution was deposited on an ITO substrate by the spin-coating technique. The samples were heat treated on a hot plate by different heat treatment conditions. To confirm that h-MoO3 thin film was successfully fabricated, the samples were then characterized by various analyses, including elementary, morphology analysis, crystalline and optical properties. The overall transmittance for MoO3 thin films on ITO ranges from 77 to 82% at the visible light spectrum (300 to 800 nm). When used in HOD, the degree of crystallinity of MoO3 thin film can be enhanced with the increase of film thickness that, compared with the conventional hole injection layer by PEDOT:PSS, shows favorable device performance.
The second part of this thesis focuses on an alternative tool of heat treatment, CO2 laser. Since the wavelength of CO2 laser light is far infrared that provides excellent thermal effect on material processing. It is expected the crystalline of MoO3 thin films can be efficiently improved. Depending on laser powers and stage scan speeds, we observed, based on SEM images, MoO3 thin films were with various microstructures, such as needle-like, flake-like and block-like. We examine their properties and discuss their formation mechanisms. |
