在本論文中，利用磁控式射頻濺鍍系統製備氧化釩薄膜應用於鈣鈦礦太陽能電池、熱阻式紅外線感測器、二氧化氮氣體感測器及記憶體選擇器等光電及電子元件上。氧化釩材料具有高可見光穿透率、高溫度電阻係數、熱穩定性、優越的催化特性與金屬-絕緣體相變(Metal-insulator transition, MIT)性質，使得其應用相當廣泛。
本論文提出一新的界面修飾層，進而改善鈣鈦礦太陽能電池元件特性，此界面修飾層是利用真空技術製備氧化釩薄膜作為界面緩衝層，結合PEDOT:PSS成為雙層電洞載子傳輸結構。增加氧化釩界面修飾層的元件較傳統僅有PEDOT:PSS作為電洞傳輸層元件，其轉換效率由9.43%提升到13.69%，主要原因為其具有較高短路電流及較佳之填充因子。同時利用紫外光譜儀分析本研究所製備氧化釩薄膜之功函數及價電子帶最大值，以推估出其能帶，進而探討其與元件能帶之匹配程度，並利用極性及非極性溶劑所量得之接觸角推估出其薄膜表面能，進行界面附著程度之分析，經分析結果可知，氧化釩相當適合作為改善鈣鈦礦太陽能電池電洞傳輸界面材料。
本論文亦針對氧化釩熱阻式微感測器進行微小尺寸特性研究，將元件設計成空腔懸浮結構，包含鋁反射鏡、空腔、支撐懸臂、電極、感測層與鉻金屬吸收層，入射紅外光與經過反射鏡反射之紅外光形成建設性干涉，大幅提升紅外線的吸收率，且懸浮結構亦可有效減少感測層與基板接觸所產生之熱散逸，以增進元件特性。
本論文同時將由黑金/氧化釩所構成的新型p-n異質接面雙感測薄膜應用於二氧化氮氣體感測器。分別使用磁控式射頻濺鍍系統和低溫氣相冷凝系統來製備氧化釩薄膜及黑金薄膜。透過分別使用黑金感測薄膜及氧化釩感測薄膜的氣體感測器檢測二氧化氮氣體，驗證黑金/氧化釩雙感測薄膜可形成p-n異質接面。由於黑金/氧化釩雙感測薄膜具有更高的體表比及可形成p-n異質接面，在100 ppm二氧化氮濃度下工作，與傳統的氧化釩氣體感測器相比，其響應度從78.78％提升到188.15％。
最後，本論文利用釩金屬作為氧化釩記憶體選擇器的上電極。利用外加偏壓來使選擇器元件產生軟性崩潰形成導通路徑(Forming)，將氧離子推向釩電極，使釩電極氧化，在釩電極和氧化釩切換層上產生具有MIT特性的相變區域，使得元件在製作過程中不需經過任何高溫退火處理即可操作。操作時只需藉由較小的閾值電壓，即可產生足夠焦耳熱，以達到相變溫度。並利用正負偏壓操作，使元件具雙極性選擇器特性。由電性量測結果得知，V/VOx/TiN選擇器表現出優越的性能，如高均勻性，短切換時間(約60 ns)，強大耐用性(可操作超過109次)以及良好的可靠度和穩定性，相信它將為高密度儲存元件克服潛行電流問題提供巨大價值。

In this dissertation, vanadium oxide (VOx) films prepared with a radio frequency (RF) magnetron sputtering system were applied to optoelectronic and electronic devices, such as perovskite solar cells (PSCs), microbolometers, nitrogen dioxide (NO2) gas sensors, and memory selectors. VOx presents characteristics of high visible light transmittance, high temperature coefficient of resistance, thermodynamic stability, excellent catalytic activity, and metal-insulator transition (MIT) properties, therefore, this substance is widely used in various fields.
A novel interface modification layer (IML) is proposed in this dissertation to improve the performance of PSCs. A VOx IML is prepared as an interface buffer layer by using an RF magnetron sputtering system. In addition, poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate) (PEDOT:PSS) is used to form a hole transport bilayer structure. Compared with conventional PSCs that do not possess a VOx IML, PSCs with a VOx IML have a 4.26% higher power conversion efficiency mainly due to their higher short-circuit current density (JSC) and fill factor. The work function and valence band maximum of the VOx films were analyzed through ultraviolet photoelectron spectroscopy. They were used to determine the energy band diagram and energy level matching. Moreover, the contact angles measured with polar and nonpolar solvents were used to estimate the surface energy of the VOx films. Subsequently, interface adhesion was analyzed. The analysis results indicated that VOx is suitable for improving the hole transport interface of PSCs and is worthy of further research.
The performance of VOx microbolometers with small sizes was also investigated. A microbolometer has as a floating-type structure, and includes an aluminum (Al) reflector, a cavity, a support cantilever, an electrode, a sensitive layer, and a chromium (Cr) metal absorption layer. The incident infrared (IR) light and the IR light reflected by the Al reflector form a constructive interference, which considerably improves the IR absorptance capability. The floating-type structure can also effectively reduce the heat loss caused by the contact between the sensitive layer and the substrate, which improves the performance of VOx microbolometers.
A novel p-n heterojunction constructed using gold black/VOx bi-sensing membranes was used in NO2 gas sensors. The VOx and gold black films were sequentially deposited on quartz substrates by using an RF magnetron sputtering system and a vapor cooling condensation system, respectively. Scanning electron microscopy and atomic force microscopy images indicated that the gold black/VOx bi-sensing membranes had a rougher surface than the VOx sensing membranes. The detection of NO2 gas by using NO2 gas sensors with gold black and VOx sensing membranes indicated that p-n heterojunction formed in the gold black/VOx bi-sensing membranes. The gold black/VOx bi-sensing membranes had a larger surface-area-to-volume ratio than the VOx membranes did. Therefore, the gas response of prepared NO2 gas sensors was improved from 78.78% to 188.15% compared with NO2 gas sensors with VOx membranes operated under 100 ppm NO2 concentration at its respectively optimal operating temperature.
Finally, vanadium (V) was used as the top electrode in a VOx-based selector device. Electroforming was performed to produce a threshold region with the MIT property at the V electrode and VOx switching layer without performing annealing during the fabrication process. The electrical measurements indicated that the V/VOx/TiN selectors had excellent characteristics, such as high uniformity, a short switching time of 60 ns, robust endurance over 109 cycles, and good reliability and stability. The developed selector can be applied in future high-density crossbar memory devices to overcome sneak-path problems.

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