本文選題：二氧化釩 + 太赫茲調(diào)制　； 參考：《電子科技大學(xué)》2017年碩士論文

【摘要】：二氧化釩(VO_2)薄膜在太赫茲波段具有良好的熱致半導(dǎo)體-金屬相變(MIT)性能,在光學(xué)調(diào)制、開關(guān)、存儲材料等領(lǐng)域有巨大的應(yīng)用前景。較低的溫度下,VO_2薄膜呈絕緣相,對THz波基本無吸收和色散作用,太赫茲透過率較高。但是隨著溫度升高超過相變溫度后,VO_2薄膜呈金屬相,薄膜的太赫茲透過率急劇的減小。我們可以通過熱、光、電等外部激勵信號控制氧化釩薄膜的相變,使太赫茲波處于透過和不透過的兩種不同狀態(tài),實現(xiàn)對太赫茲波的調(diào)制。VO_2薄膜在THz波段的相變特性,為研究和制備超高速、高調(diào)制深度并能在室溫附近工作的THz調(diào)制器件,填補(bǔ)THz波段缺乏調(diào)控材料和器件的缺陷,促進(jìn)THz波段器件的實際應(yīng)用具有重要的科學(xué)意義和應(yīng)用價值。為了實現(xiàn)氧化釩薄膜在太赫茲調(diào)制器件上的應(yīng)用,要求氧化釩薄膜具有好的穩(wěn)定性和可靠性、高的響應(yīng)率和效率,VO_2應(yīng)滿足四個方面的性能要求:(1)半導(dǎo)體態(tài)具有較高的太赫茲透過率;(2)較大的太赫茲調(diào)制深度;(3)較小的回線寬度;(4)較低的相變溫度。本論文主要圍繞制備良好太赫茲調(diào)制性能的氧化釩薄膜展開,立足現(xiàn)階段缺乏高調(diào)制幅度的氧化釩薄膜為基點,開展了以下兩部分工作:(1)在高阻Si(100)襯底上,利用直流反應(yīng)磁控濺射法制備相變氧化釩薄膜,探究工藝參數(shù)(反應(yīng)氧流量和濺射電流)對氧化釩MIT性能的影響。在探究工藝參數(shù)的實驗中,發(fā)現(xiàn)靶表面狀態(tài)的不同也影響著氧化釩的性能,尤其是太赫茲波段的調(diào)制深度。進(jìn)而探究靶表面狀態(tài)對氧化釩薄膜太赫茲調(diào)制深度的影響,在平整靶表面狀態(tài)下制備了在4.8~6THz波段室溫太赫茲透過率約為87%,高溫太赫茲透過率約為6%,平均調(diào)制深度為93%的氧化釩薄膜。(2)在平整靶表面狀態(tài)下制備的氧化釩薄膜,雖然在4.8~6THz波段具有高調(diào)制深度,但是該薄膜回線寬度較寬(12.4℃),相變溫度較高(67.5℃),不能完全滿足氧化釩薄膜應(yīng)用到太赫茲器件的四個性能要求,所以采用貼片法摻雜(Mo和W)來降低薄膜的回線寬度和相變溫度。在保持優(yōu)良太赫茲調(diào)制深度(4.8~6THz,83%)的同時,通過摻W(1.5at.%)制備出回線寬度較小(7.7℃),相變溫度低(49.1℃)的氧化釩薄膜。
[Abstract]:Vanadium oxide VO _ 2) thin films have good thermo-induced semiconductor-metal phase transition (mitt) properties in terahertz band, and have great application prospects in optical modulation, switching, storage materials and so on. VO _ 2 thin films are insulated at low temperature and have no absorption and dispersion effect on THz wave. The terahertz transmittance is high. However, the THz transmittance of VO _ 2 thin films decreases dramatically when the temperature exceeds the phase transition temperature. The phase transition of vanadium oxide thin films can be controlled by external excitation signals, such as heat, light and electricity, so that the terahertz wave is in two different states of transmission and non-transmission. The modulation of terahertz wave and the phase transition of VO2 thin film in THz band can be realized. In order to study and fabricate ultra-high speed, high modulation depth THz modulation devices which can work near room temperature, it is of great scientific significance and application value to fill the defects of THz band lacking of control materials and devices, and to promote the practical application of THz band devices. In order to realize the application of vanadium oxide thin film in terahertz modulation device, the vanadium oxide film is required to have good stability and reliability. The high response rate and efficiency should meet the requirements of four aspects: 1) the semiconductor state has higher terahertz transmittance and 2) the larger terahertz modulation depth is 3) the smaller loop width and the lower phase transition temperature. This thesis focuses on the preparation of vanadium oxide thin films with good terahertz modulation performance. Based on the lack of high modulation amplitude vanadium oxide thin films at present, the following two parts of work are carried out: 1) on high resistivity Si Si 100) substrates. Phase change vanadium oxide thin films were prepared by DC reactive magnetron sputtering. The effects of process parameters (reactive oxygen flow rate and sputtering current) on the properties of vanadium oxide MIT were investigated. It is found that the different surface states of the target also affect the performance of vanadium oxide, especially the modulation depth of terahertz band. Then the effect of the target surface state on the terahertz modulation depth of vanadium oxide thin films was investigated. Vanadium oxide thin films were prepared under the condition of leveling target surface at 4.8THz room temperature terahertz transmittance of about 87, high temperature terahertz transmittance about 6, average modulation depth of 93% vanadium oxide thin films under flat target surface condition. Although it has a high modulation depth in the 4.8 THz band, the loop width of the thin film is wider than 12.4 鈩，

本文編號：2039814