多色彩奈米矽基金氧半發光二極體

Abstract

在本論文中，我們主要是利用電漿輔助化學氣相沉積(PECVD)技術法，藉由改變電漿的射頻功率等製程參數，提出可調控式富矽氧化矽(Si rich SiOx)薄膜層中光激螢光波長之方法。 經由穿透式電子顯微鏡X光能量散射光譜儀(TEM-XEDS)的結果指出當電漿射頻功率增加時，富矽氧化矽層中的氧/矽組成比例，也隨之逐漸提高。在經過高溫退火後，氧化矽層中的奈米矽晶粒的平均大小，隨著氧化矽層中的氧/矽組成比例增高而變小。換言之，可藉由改變電漿的射頻功率與高溫熱退火處理技術，來調控富矽奈米矽晶粒的顆粒大小。同時藉由不同尺寸的奈米粒子所產生之量子效應可得到對應於奈米矽晶粒大小相關的可調之光激螢光光譜波長，其螢光光譜範圍可從390 nm到780 nm。 此外，論文中也針對富矽奈米矽基金氧半發光二極體元件的電激螢光(EL)特性加以討論。由I-V結果顯示，在電漿射頻功率由50 W增加到70 W所製備的元件，其起始操作電壓均呈現非線性的增加，但是起始操作電場強度卻維持在6.6 × 10^6 V/cm，進一步經由光學顯微鏡拍攝此系列參數於正向電流注入下之發光圖像，可分別得到红色、綠色和藍色的電激螢光影像，這結果也驗證經由製成參數調控所製備的不同尺寸大小之富矽奈米矽粒子，於EL結果中呈現藍位移的現象。

By changing the RF plasma power during the PECVD system, photoluminescence (PL) wavelength control of Si-rich SiOx film was proposed. The O/Si composition ratio increased as the RF power increased, which was confirmed by TEM XEDS. After high temperature annealing, the average sizes of the nc-Si embedded in the SiOx film decreased when the O/Si composition ratio in the SiOx film increased. We could control the O/Si composition ratio in the SiOx film by detuning RF plasma power in the PECVD system, which leads to different sizes of Si nanocrystals after high-temperature annealing. Hence, we could obtain nc-Si size-related and wavelength-tunable PL spectrum from 390 to 780 nm. Subsequently, the EL properties of PECVD–grown Si-rich SiOx based MOSLED was investigated. The turn-on voltage of the Si-rich SiOx film increased as the RF plasma power increased from 50 to 70 W, resulting in the same operational electric field strength at 6.6 × 10^6 V/cm for such nc-Si based devices. The EL microscopy images of device under RF plasma power of 50, 60 and 70 W revealed the red, green, and blue emission under forward bias current to the Si substrate. A significant size-dependent blueshift was clearly shown.