本文選題：氧化鋅　切入點(diǎn)：納米線　出處：《北京科技大學(xué)》2015年博士論文　論文類型：學(xué)位論文

【摘要】：ZnO是一種直接寬帶隙半導(dǎo)體材料,禁帶寬度在室溫下約為3.37eV,天然呈n型半導(dǎo)體導(dǎo)電特性,常見的結(jié)構(gòu)為六方纖鋅礦結(jié)構(gòu)。而一維ZnO納米材料獨(dú)特的納米效應(yīng)極大地改善了其光電性能,在太陽能電池、紫外探測、光解水制氫等領(lǐng)域顯示出了廣闊的應(yīng)用前景。本文采用水熱法和化學(xué)氣相沉積法制備了不同形貌的一維ZnO納米材料,并深入研究了其自驅(qū)動光電響應(yīng)機(jī)理。在此基礎(chǔ)上,系統(tǒng)地探究了光敏化劑ZnIn2S4和CdS對一維ZnO納米材料光電化學(xué)性能的影響。 分別用水熱法和化學(xué)氣相沉積法制備了ZnO納米線陣列和ZnO納米線。合成的一維ZnO納米材料都具有六方纖鋅礦結(jié)構(gòu),沿[0001]方向生長,結(jié)晶質(zhì)量高,缺陷少。利用實(shí)驗(yàn)和模擬相結(jié)合的方法推算出了化學(xué)氣相沉積法制備的單根ZnO納米線的電子濃度和電子遷移率分別為1.06×1017cm-3和1.68cm2v-1s-1。 研究了單根ZnO納米線和p型硅薄膜所形成的異質(zhì)pn結(jié)的自驅(qū)動光電響應(yīng)性能。電學(xué)性能測試表明,該異質(zhì)結(jié)有明顯的整流特性,整流比高達(dá)103,按照熱電子發(fā)射理論計(jì)算,其理想因子為2。異質(zhì)結(jié)在負(fù)偏壓時(shí)對紫外光和可見光都有響應(yīng),在正偏壓時(shí),只對紫外光有響應(yīng)。零偏壓時(shí),對紫外光的響應(yīng)靈敏度達(dá)到2×104,對可見光的響應(yīng)靈敏度為5×103,響應(yīng)時(shí)間約為7.4ms。零偏壓時(shí)的光電流和入射光的強(qiáng)度成平方根關(guān)系,開路電壓與入射光的強(qiáng)度成對數(shù)關(guān)系。 分別研究了ZnO納米線網(wǎng)和ZnO納米線陣列的自驅(qū)動光電響應(yīng)性能。ZnO納米線網(wǎng)和Pt電極之間形成肖特基接觸,零偏壓時(shí)對紫外光的響應(yīng)靈敏度達(dá)到800。構(gòu)建了Pt/ZnO納米線陣列/Pt結(jié)構(gòu)自驅(qū)動紫外探測器,器件兩端的肖特基勢壘高度不同引起了自驅(qū)動現(xiàn)象。當(dāng)勢壘高度差為30meV時(shí),器件對紫外光的響應(yīng)靈敏度達(dá)到475�？疾炝藴囟葘l/ZnO納米線陣列/Pt結(jié)構(gòu)單肖特基型自驅(qū)動紫外探測器性能的影響。溫度低于340K時(shí),光電流隨溫度升高而增大,溫度繼續(xù)升高,光電流減小。溫度高于420K時(shí),電極被氧化,器件發(fā)生損壞。 研究了ZnO納米線陣列／還原氧化石墨烯(RGO)/ZnIn2S4異質(zhì)結(jié)構(gòu)的光電化學(xué)性能。結(jié)構(gòu)分析表明,生成的ZnIn2S4屬于六方晶系。經(jīng)過還原處理后,RGO中含氧官能團(tuán)的量降為27%。ZnO納米線陣列復(fù)合了RGO和ZnIn2S4之后,對可見光的吸收能力明顯增強(qiáng),在500nm處出現(xiàn)較弱的吸收峰。該異質(zhì)結(jié)構(gòu)的光轉(zhuǎn)氫效率比純ZnO納米線陣列提高了2倍,達(dá)到了0.46%。RGO的引入增加了光陽極的表面積,促進(jìn)了光生載流子在ZnO和ZnIn2S4之間的傳輸。另外,ZnIn2S4增強(qiáng)了光陽極對可見光的吸收效率,進(jìn)而提高了其光轉(zhuǎn)氫效率。 研究了3D樹枝狀ZnO/CdS復(fù)合材料的光電化學(xué)性能。3D樹枝狀ZnO/CdS復(fù)合材料的光轉(zhuǎn)氫效率比純ZnO納米線陣列有大幅提升,達(dá)到了1.62%。3D樹枝狀結(jié)構(gòu)的ZnO納米線陣列具有更高的表面粗糙度和更大的表面積,這增強(qiáng)了光陽極的光吸收能力,促進(jìn)了載流子在固／液界面的傳輸。同時(shí),CdS的引入提高了光陽極在可見光區(qū)域的光催化活性,CdS和ZnO之間形成的空間電場,加速了光生載流子的分離。另外,本文還研究了3D樹枝狀ZnO/CdS復(fù)合材料的光腐蝕問題,并用原子層沉積法(ALD)在光陽極表面沉積Ti02保護(hù)層,提高了其光電化學(xué)穩(wěn)定性。
[Abstract]:ZnO is a direct wide band gap semiconductor material, the band gap at room temperature is about 3.37eV, a natural conductive properties of N type semiconductor, a common structure for the six wurtzite structure. And the effect of nano ZnO nanomaterials were unique to improve the photoelectric properties in solar cell, UV detection, field water photolysis shows a broad application prospect. This paper adopts the hydrothermal method and chemical vapor one-dimensional ZnO nanomaterials with different morphologies were prepared by deposition, and in-depth study of its self driving photoelectric response mechanism. On this basis, systematically explores the photosensitizing agents ZnIn2S4 and CdS on ZnO nanowires the photoelectrochemical properties of the material.
Respectively using hydrothermal method and chemical vapor ZnO nanowires and ZnO nanowires were prepared by deposition. One dimensional ZnO nano materials synthesis has six wurtzite structure. The growth along the [0001] direction, high crystalline quality, less defects. On the basis of experiment and simulation to calculate the electron density and electron transfer the chemical vapor deposition of single ZnO nanowires prepared by the rate of 1.06 * 1017cm-3 and 1.68cm2v-1s-1.
Study of single ZnO nanowire and P type silicon thin film formed by PN heterojunction self driving photoelectric response performance. Electrical performance tests show that there are clear rectifying properties of the heterojunction, rectifying ratio as high as 103, calculated in accordance with the thermionic emission theory, the ideal factor is in the negative bias are in response to ultraviolet light and 2. in the visible light heterojunction, positive bias, only response to UV light. The zero bias, sensitivity to UV light reached 2 * 104, the response sensitivity of visible light is 5 * 103, the response time is about the photocurrent and incident light 7.4ms. zero bias when the intensity of the relationship between the square root. The open circuit voltage and the intensity of the incident light into a logarithmic relationship.
Self driving photoelectric response Schottky contact formed between the properties of.ZnO nanowires and Pt nanowires of ZnO electrode and ZnO nanowire arrays were studied. The zero bias sensitivity to UV light reached 800. constructed self driven UV detector of Pt/ZnO nanowire arrays /Pt, Schottky barrier devices at both ends of the different height caused by self driving phenomenon. When the barrier height difference is 30meV, sensitivity to UV device reached 475. to investigate the effect of temperature on Al/ZnO nanowire arrays /Pt structure of single Schottky type self driven UV detector performance. The temperature is lower than 340K, the photocurrent increases with the temperature, the temperature continues to rise, the light current temperature decreases. Above 420K, the electrode is oxidized, device damage.
Research on ZnO nanowire arrays / reduced graphene oxide (RGO) photoelectrochemical properties of /ZnIn2S4 heterostructures. The structural analysis shows that the generated ZnIn2S4 belongs to the six party system. After reduction treatment, after oxygen containing functional groups in RGO was reduced to 27%.ZnO composite nanowire arrays RGO and ZnIn2S4, the visible light absorption ability increased, there was an absorption peak at 500nm is weak. The heterostructure light transfer efficiency of hydrogen than pure ZnO nanowires increased 2 times, reaching the introduction of 0.46%.RGO increases the light anode surface area, promote the transfer of the photogenerated carriers between ZnO and ZnIn2S4. In addition, ZnIn2S4 enhanced the absorption the efficiency of light anode of visible light, and then increase the light conversion efficiency of hydrogen.
Study on the photoelectrochemical properties of.3D dendritic ZnO/CdS composite 3D dendritic ZnO/CdS composite light conversion efficiency of hydrogen than pure ZnO nanowire arrays have increased dramatically, reaching ZnO nanowires 1.62%.3D dendritic structure array has higher surface roughness and larger surface area, which enhances the ability to absorb light the anode of light, to promote the transfer of carriers in solid / liquid interface. At the same time, the introduction of CdS improves light anode photocatalytic activity in the visible region of the space electric field is formed between CdS and ZnO, accelerates the separation of photogenerated carriers. In addition, this paper also studied the light corrosion problem of dendritic 3D ZnO/CdS composite material, and using atomic layer deposition (ALD) deposited on the anode surface light Ti02 protective layer, improves the photoelectric chemical stability.

【學(xué)位授予單位】：北京科技大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2015
【分類號】：TB383.1;O614.241

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本文編號：1559211