【摘要】：在當(dāng)今這個科技快速發(fā)展的時代,探測技術(shù)存在于世界的各個角落,而紫外探測早已成為了一種兼具實用和發(fā)展前景的新探測技術(shù)。已廣泛應(yīng)用到火焰檢測、天文探測、光波通信、成像技術(shù)以及光電集成電路等領(lǐng)域。研制一種低成本、響應(yīng)度高、噪聲電流低、響應(yīng)速度快且探測靈敏度高的紫外光電探測器迫在眉睫。到目前為止,寬禁帶半導(dǎo)體材料紫外探測器在低維度納米材料的合成方面有較大優(yōu)勢。但是單一半導(dǎo)體材料的缺點較為明顯,例如器件響應(yīng)度受材料所限無法得到突破性提升,暗電流較大,響應(yīng)恢復(fù)速度較慢等。近年來,人們通過各種方法來改善器件性能,其中制備復(fù)合材料形成異質(zhì)結(jié)就是一種通過利用材料的能級差提高器件性能的有效方式。本論文利用一維二氧化鈦(TiO_2)納米材料作為基礎(chǔ),制備出鈦酸鍶(SrTiO_3)/TiO_2和鈦酸鋇(BaTiO_3)/TiO_2異質(zhì)復(fù)合材料,并制作成紫外光電探測器。通過進行相關(guān)的表征和器件性能測試來深入探索其光電性能及工作原理。本論文首先采用低溫極性水解法制備一維TiO_2納米線陣列。通過SEM表征結(jié)果顯示納米線在FTO襯底上分布均勻、生長致密。豎直方向分叉明顯,尖端無粘連,表現(xiàn)出一維半導(dǎo)體的形貌特征。其高比表面積和高載流子傳輸效率,為接下來制作高性能的異質(zhì)結(jié)紫外光電探測器打下良好的基礎(chǔ)。接下來通過二次水熱原位生長法制備SrTiO_3/TiO_2異質(zhì)結(jié)材料,其中作為第一步水熱反應(yīng)產(chǎn)物的TiO_2納米線,將在第二步水熱反應(yīng)中同時充當(dāng)異質(zhì)結(jié)生長基底和原位生長的反應(yīng)物,能有效減少雜質(zhì)的摻入。異質(zhì)結(jié)的生長過程基于奧斯特瓦爾德熟化效應(yīng),在保持材料一維結(jié)構(gòu)特性的同時,將在納米線之間形成網(wǎng)狀結(jié)構(gòu),提高照光面積。復(fù)合材料表現(xiàn)出良好的紫外區(qū)域光譜吸收選擇性,并且由于兩種材料禁帶寬度的差異,表現(xiàn)出光譜響應(yīng)的藍移特性,所以器件的光響應(yīng)波長范圍具有一定的可調(diào)性。對比SrTiO_3/TiO_2和單一TiO_2器件性能,異質(zhì)結(jié)器件在光暗電流比、光響應(yīng)度和恢復(fù)速度等參數(shù)上有較大突破,這歸功于能級的差異促進光生載流子分離等效應(yīng),具體的機理分析將于文中詳細給出。最后本論文將拓寬對原位生長異質(zhì)結(jié)復(fù)合材料的研究,通過二次水熱原位生長法制備BaTiO_3/TiO_2異質(zhì)結(jié)材料,SEM表征結(jié)果顯示異質(zhì)結(jié)的生長將填充部分納米線間的空隙,并且在不斷增大前驅(qū)反應(yīng)物量時,將會導(dǎo)致納米線形貌被破壞。復(fù)合材料表現(xiàn)出較好的紫外區(qū)域光譜吸收選擇性以及光譜響應(yīng)的紅移特性。基于BaTiO_3/TiO_2異質(zhì)結(jié)的紫外光電探測器性能相對于單一的TiO_2器件會有所提升,這將在文中給出詳細機理解釋。本文制備了TiO_2納米線陣列和兩種基于TiO_2的異質(zhì)結(jié)復(fù)合材料,并制作成器件應(yīng)用于紫外探測領(lǐng)域。研制的器件在性能方面有較大的提升,文中對各項參數(shù)的變化都進行了深入探討,這將為今后對紫外探測技術(shù)的研究打下良好的基礎(chǔ)。
[Abstract]:Nowadays, with the rapid development of science and technology, detection technology exists in all corners of the world, and ultraviolet detection has already become a new detection technology with both practical and development prospects. UV photodetectors with high intensity, low noise current, fast response speed and high detection sensitivity are imminent. So far, wide band gap semiconductor UV detectors have great advantages in the synthesis of low-dimensional nanomaterials. In recent years, a variety of methods have been used to improve the performance of devices. Among them, the formation of heterojunctions by fabricating composite materials is an effective way to improve the performance of devices by utilizing the energy level difference of materials. Based on this, strontium titanate (SrTiO 3) / titanium dioxide (TiO 2) and barium titanate (BaTiO 3) / titanium dioxide (TiO 2) heterostructure composites were prepared and fabricated into ultraviolet photodetectors. The results show that the nanowires are uniformly distributed and densely grown on the FTO substrate. The vertical bifurcation is obvious and the tip is non-adhesive. The nanowires exhibit the morphological characteristics of one-dimensional semiconductor. SrTiO_3/TiO_2 heterojunction materials were prepared by thermal in-situ growth method. As the product of the first step hydrothermal reaction, TiO_2 nanowires will act as both the substrate for heterojunction growth and the reactant for in-situ growth in the second step hydrothermal reaction, which can effectively reduce the doping of impurities. Holding the one-dimensional structural characteristics of the materials, the nanowires will form a network structure between the nanowires to improve the illumination area. The composites show good spectral absorption selectivity in the ultraviolet region. Moreover, because of the difference of band gap between the two materials, they show blue shift characteristics of spectral response, so the wavelength range of optical response of the devices is certain. Compared with the performance of SrTiO_3/TiO_2 and single TiO_2 devices, the heterojunction devices have made great breakthroughs in the parameters of light-dark current ratio, light responsiveness and recovery speed, which is attributed to the difference of energy levels promoting the effect of photogenerated carrier separation. The detailed mechanism analysis will be given in this paper. Finally, the in-situ growth heterogeneity will be broadened. BaTiO_3/TiO_2 heterojunction materials were prepared by two-step hydrothermal in-situ growth method. SEM characterization showed that the growth of heterojunction would fill the gap between some nanowires, and the morphology of nanowires would be destroyed when the amount of precursor reactants increased. Absorption selectivity and red shift characteristics of spectral response. The performance of ultraviolet photodetectors based on BaTiO_3/TiO_2 heterojunctions will be improved compared with single TiO_2 devices. Detailed explanation of the mechanism will be given in this paper. In this paper, two nanowire arrays and two heterojunction composites based on TiO_2 have been prepared and fabricated and applied to devices. In the field of ultraviolet detection, the performance of the device has been greatly improved. Variations of various parameters are discussed in detail, which will lay a good foundation for the future research of ultraviolet detection technology.
【學(xué)位授予單位】：吉林大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TN23

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相關(guān)期刊論文 前1條

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本文編號：2234999