本文選題：釩酸鉍 + 正溫度系數效應��； 參考：《安徽理工大學》2015年碩士論文

【摘要】：釩酸鉍(BiVO4)是優(yōu)異的半導體功能材料,因其獨特的晶體結構和性能引起了眾多科研工作者的關注。目前關于BiVO4單晶以及多晶陶瓷方面的研究少之又少,對其本征的性能認識還不夠。因此本論文以BiVO4晶體與陶瓷為研究對象,對其晶體的生長與性能及陶瓷的制備工藝與電學性能展開研究。論文主要內容如下： 第一章為緒論部分。本章首先介紹了BiVO4材料的晶體結構及基本性質。然后重點介紹了BiVO4材料的研究進展和電阻正溫度系數效應。最后對論文的選題背景及研究意義進行了介紹了并確定了論文的主要研究內容。 第二章主要研究了BiVO4晶體的坩堝下降法生長與性能。首次發(fā)現BiVO4晶體表面接觸角隨光照時間呈現先減小后增大的變化規(guī)律,同時電阻率呈現正溫度系數效應。 第三章主要研究了燒結條件對BiVO4陶瓷物相組成、顯微結構、介電、阻抗、電阻率等性能的影響。發(fā)現當燒結溫度大于820℃時陶瓷表面開始出現玻璃相,說明Bi容易在晶界處發(fā)生成分偏析。此外發(fā)現BiVO4陶瓷兩個介電弛豫損耗峰。而且BiVO4陶瓷在測試電阻率隨溫度的變化關系時表現出明顯的正溫度系數效應,并對其形成機理進行了探討。 第四章主要研究了La3+摻雜比例對Bi1-xLaxVO4陶瓷電學性能的影響。發(fā)現La3+摻雜能顯著降低單斜Bi1-xLaxVO4固溶體陶瓷的介電損耗,降低陶瓷的導電性。而且Bi1-xLaxVO4(0.05≤x≤0.20)陶瓷的lgp-T曲線在200℃附近出現拐點,說明其電流傳輸機理在低溫與高溫下不同。 第五章主要研究了V5+位摻雜M6+(M:Mo、W)對BiVO4陶瓷電學性能的影響。發(fā)現Mo元素摻雜可以顯著的降低BiVO4陶瓷的介電損耗,且Bi1-x/Φx/3V1-xWxO4陶瓷介電頻譜中存在的兩個介電損耗峰具有典型的弛豫特征。W元素摻雜對Bi1-x/Φx/3V1-xWxO4陶瓷電阻率的改變較為顯著,x=0.06、0.18的Bi1-x/Φx/3V1-xWxO4陶瓷樣品在200C-750C范圍內電阻率增大的幅度達到2-3個數量級,PTC效應非常明顯。 第六章是對論文主要結果和創(chuàng)新之處的總結以及對未來BiVO4材料研究趨勢的展望。
[Abstract]:Bismuth vanadate (BiVO4) is an excellent semiconductor functional material, which has attracted many researchers' attention because of its unique crystal structure and properties.At present, there are few researches on BiVO4 single crystal and polycrystalline ceramics.Therefore, the growth and properties of BiVO4 crystals and ceramics, the preparation process and electrical properties of ceramics were studied in this paper.The main contents of the thesis are as follows:The first chapter is the introduction.In this chapter, the crystal structure and basic properties of BiVO4 are introduced.Then the research progress of BiVO4 material and the effect of positive temperature coefficient of resistance are introduced.Finally, the background and significance of the thesis are introduced and the main research contents are determined.In chapter 2, the growth and properties of BiVO4 crystals by crucible descent method are studied.It is found for the first time that the surface contact angle of BiVO4 crystal decreases first and then increases with the illumination time, and the resistivity shows a positive temperature coefficient effect.In chapter 3, the effects of sintering conditions on the phase composition, microstructure, dielectric, impedance and resistivity of BiVO4 ceramics are studied.It is found that when the sintering temperature is higher than 820 鈩，

本文編號：1770470