本文選題：ZnO薄膜　切入點：ZnMgO薄膜　出處：《浙江大學》2015年博士論文

【摘要】：ZnO室溫下的禁帶寬度為3.37 eV,吸收邊位于紫外波段,在可見光區(qū)透明,與MgO合金化得到的更寬禁帶的ZnMgO薄膜可應用在深紫外光電器件中。摻入A1、Ga和F等施主摻雜劑可以有效地改善ZnO的本征n型導電性能�？萍嫉倪M步促使電子器件朝柔性化、超薄化方向發(fā)展,迫切需要發(fā)展柔性透明導電材料。因此,制備柔性透明導電ZnO基材料具有非常重要的現(xiàn)實意義。在本論文中,我們采用脈沖激光沉積技術(PLD, Plused Laser Deposition)制備了F摻雜ZnMgO (ZMOF)透明導電薄膜,此外,為了滿足柔性器件的應用要求,我們還開展了柔性；ZMOF透明導電薄膜的研究。由于制備高質量、可重復并穩(wěn)定存在的p型ZnO仍是一個難點,導致ZnO同質結器件的制備困難,因此,選用p型NiO與n型ZnO制備的ZnO基異質結器件受到廣泛關注。在ZnO/NiO異質結的基礎上,我們通過調節(jié)Mg含量來制備不同禁帶寬度的Ni1-xMgxO薄膜,與ZnO和ZnMgO制備成異質結器件并深入研究其能帶結構。1.采用PLD方法在石英襯底上制備了ZMOF薄膜。350。C,0.001 Pa條件下制備的ZMOF薄膜(3 at.%的F,10 at.%的Mg)具有最好的光電性能,電阻率最低為6.92×10-4 Ωcm,在整個可見光區(qū)的透過率超過85%,且用濕法腐蝕方法制備了絨面ZMOF薄膜。2.利用PLD技術在柔性襯底上制備了ZMOF薄膜,通過引入ZnO緩沖層,提高了薄膜晶體質量,消除了裂紋,電阻率從1.55 Ωcm降低到1.70x10-2Ωcm,遷移率從0.573 cm2V-1s-1升高到11.7 cm2V-1s-1,大大提高了其電學性能。3.利用磁控濺射儀器對以F摻雜ZnO (FZO)為代表的ZnO基薄膜進行了真空退火和H等離子體處理。處理后的FZO薄膜結晶質量更好,電學性能更優(yōu),尤其是遷移率實現(xiàn)了3-10倍的增長。我們通過第一性原理計算研究了H在FZO中的位置及能態(tài),發(fā)現(xiàn)在ZnO晶格中靠近Fo的間隙位的氫(Hi-Fo)和處于氧空位中的氫(H-Vo)都可以穩(wěn)定存在,這是H處理后FZO透明導電薄膜高導電性、高熱穩(wěn)定性的原因。4.利用PLD技術生長了一系列不同Mg含量的Ni1-xMgxO薄膜,且制備了可探測日盲區(qū)的光導型光電探測器。通過快速退火處理提高了薄膜晶體質量,降低了器件暗電流。為了探討Mg的引入對ZnO/NiO異質結能帶結構的影響,我們制備了不同Mg含量的ZnO/Ni1-xMgxO異質結,通過X射線光電子能譜方法研究了異質結的能帶結構。研究發(fā)現(xiàn),Mg含量越高,導帶帶階和價帶帶階偏移量均越大,導帶帶階移動量更大。我們進一步開展了雙邊帶隙可調節(jié)的Zn1-XMgxO/Ni1-yMgyO異質結的能帶結構研究,發(fā)現(xiàn)含有相同Mg組分的ZnMgO和NiMgO, Mg對兩者能帶調節(jié)的作用幅度不同,在ZnMgO中的能帶調節(jié)作用更為明顯。因此,我們可以通過分別調節(jié)Zn1-XMgxO/Ni1-yMgyO異質結中的Mg含量,來改變雙邊的禁帶寬度及價帶頂、導帶底的位置,進而設計出所需能帶結構的異質結,靈活掌控其在光電器件中的應用。
[Abstract]:The band gap of ZnO is 3.37 EV at room temperature, and the absorption edge is in the ultraviolet band. The wider ZnMgO films alloyed with MgO can be used in deep ultraviolet optoelectronic devices.The intrinsic n-type conductivity of ZnO can be effectively improved by adding donor dopants such as A _ 1, Ga, F and so on.Advances in science and technology promote the development of electronic devices in the direction of flexibility and thinning. It is urgent to develop flexible transparent conductive materials.Therefore, the preparation of flexible transparent conductive ZnO based materials has very important practical significance.In this thesis, we have prepared F-doped ZnMgO (ZMOF) transparent conductive thin films by pulsed laser deposition technique (PLD, Plused Laser deposition). In addition, in order to meet the application requirements of flexible devices, we have also carried out the research of flexible ZMOF transparent conductive thin films.Due to the difficulty of preparing high quality, repeatable and stable p-type ZnO, it is difficult to fabricate ZnO homojunction devices. Therefore, the ZnO based heterojunction devices fabricated by p-type NiO and n-type ZnO have attracted wide attention.On the basis of ZnO/NiO heterojunction, Ni1-xMgxO thin films with different bandgap were prepared by adjusting mg content. Heterojunction devices were fabricated with ZnO and ZnMgO.ZMOF thin films prepared on quartz substrates by PLD method have the best optoelectronic properties. The ZMOF films prepared at 3.350.Cn0. 001 Pa have the best optoelectronic properties.The lowest resistivity is 6.92 脳 10 ~ (-4) 惟 路cm, and the transmittance in the whole visible region is more than 850.Furthermore, the suede ZMOF film .2is prepared by wet etching method.ZMOF thin films were prepared on flexible substrates by PLD technique. By introducing ZnO buffer layer, the crystal quality of the films was improved and the cracks were eliminated. The resistivity decreased from 1.55 惟 cm to 1.70x10-2 惟 cm, and the mobility increased from 0.573 cm2V-1s-1 to 11.7 cm-2 V-1s-1, which greatly improved the electrical properties of the films.F doped ZnO / FZO thin films were annealed in vacuum and treated by H plasma with magnetron sputtering instrument.The treated FZO films have better crystallization quality and better electrical properties, especially the mobility increases 3-10 times.We have studied the position and energy states of H in FZO by first-principles calculation. It is found that both the H ~ (2 +) -H _ (-Fo) and H _ (H _ (H) -Vo) exist stably in the ZnO lattice near the gap potential of Fo and in the oxygen vacancy.This is the reason for the high conductivity and high thermal stability of FZO transparent conductive films after H treatment.A series of Ni1-xMgxO thin films with different mg content were grown by PLD technique, and photoconductive photodetectors with detectable diurnal blind area were fabricated.Through rapid annealing, the quality of thin film crystal is improved and the dark current of the device is reduced.In order to investigate the influence of mg on the energy band structure of ZnO/NiO heterojunction, ZnO/Ni1-xMgxO heterostructure with different mg content was prepared. The band structure of ZnO/Ni1-xMgxO heterojunction was studied by X-ray photoelectron spectroscopy (XPS).It is found that the higher the mg content, the greater the migration of the conduction band order and the valence band order, and the greater the movement of the conduction band order.We have further studied the band-gap tunable Zn1-XMgxO/Ni1-yMgyO heterostructures. It is found that ZnMgO and NiMgO with the same mg component have different amplitudes of energy band regulation, especially in ZnMgO.Therefore, by adjusting the mg content in Zn1-XMgxO/Ni1-yMgyO heterojunction, we can change the band gap and the position of the top and bottom of the conduction band respectively, and then design the heterojunction with the required energy band structure, and control its application in optoelectronic devices flexibly.
【學位授予單位】：浙江大學
【學位級別】：博士
【學位授予年份】：2015
【分類號】：TB383.2

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