發(fā)布時(shí)間：2018-03-17 07:24

  本文選題：硅量子點(diǎn)　切入點(diǎn)：異質(zhì)結(jié)　出處：《華中科技大學(xué)》2016年博士論文　論文類型：學(xué)位論文

【摘要】：硅量子點(diǎn)材料因具有獨(dú)特的量子效應(yīng)被廣泛應(yīng)用于光電子和微電子器件中,文中闡述了采用等離子增強(qiáng)化學(xué)氣相沉積和熱退火工藝制備硅量子點(diǎn)的工藝流程,并對(duì)不同退火條件下制備的富硅SiC:H薄膜進(jìn)行了表征分析,證明了退火處理后樣品中硅量子點(diǎn)的存在。制備了Si-rich a-SiC:H/c-Si異質(zhì)結(jié)構(gòu),通過改變退火條件,研究了Si-rich a-SiC:H薄膜中微結(jié)構(gòu)演變與Si-rich a-SiC:H/c-Si異質(zhì)界面能帶分布之間的關(guān)系,實(shí)現(xiàn)了對(duì)Si-rich a-SiC:H/c-Si異質(zhì)界面能帶帶階的調(diào)整。Si-rich a-SiC:H/c-Si異質(zhì)界面的能帶分布主要受薄膜中量子點(diǎn)結(jié)晶度、量子點(diǎn)尺寸和Si與SiC量子點(diǎn)比例等因素的影響,異質(zhì)界面能帶調(diào)控有助于改善載流子的界面?zhèn)鬏斕匦院吞岣弋愘|(zhì)結(jié)器件的性能。為探索硅量子點(diǎn)材料在異質(zhì)界面能帶調(diào)控中的應(yīng)用前景,通過模擬仿真研究了硅基異質(zhì)結(jié)太陽(yáng)能電池界面能帶分布對(duì)界面?zhèn)鬏斝阅艿挠绊憽＝?jīng)過對(duì)硅基異質(zhì)結(jié)界面能帶的分析,最終獲得硅基異質(zhì)結(jié)太陽(yáng)能電池的光電轉(zhuǎn)換效率為27.37%(開路電壓為805.5 mV,短路電流密度為41.85 mA/cm2,填充因子為81.2%)。另外,以采用MOCVD工藝制備的摻硼ZnO(BZO)薄膜作為透明電極制備了硅基異質(zhì)結(jié)太陽(yáng)能電池,研究了B2H6流量和襯底溫度對(duì)BZO薄膜微結(jié)構(gòu)、光學(xué)和電學(xué)性能的影響；當(dāng)B2H6流量約為10 sccm和村底溫度約為170℃時(shí),優(yōu)化得到的BZO薄膜的電學(xué)參數(shù)范圍為：電阻率為9.0～1.0×10-3 Ω cm,電子遷移率為16.5-25.5 cm2/Vs,載流子濃度為2.2～2.7×1020cm-3。將優(yōu)化后的BZO薄膜用于硅基異質(zhì)結(jié)太陽(yáng)能電池,并與以ITO透明導(dǎo)電薄膜作為透明電極的異質(zhì)結(jié)太陽(yáng)能電池進(jìn)行了對(duì)比分析,發(fā)現(xiàn),以BZO薄膜作為透明電極的太陽(yáng)能電池的η為17.788%,Voc為0.628 V,Jsc為41.756 mA/cm2,填充因子為0.678；以ITO薄膜作為硅基異質(zhì)結(jié)太陽(yáng)能電池的的η為16.443%,Voc為0.590 V, Jsc為36.515 mA/cm2,填充因子為0.762,以BZO薄膜作為前后透明電極的硅基太陽(yáng)電池比以ITO作為透明電極的太陽(yáng)能電池具有更好的光電轉(zhuǎn)換性能。在電荷存儲(chǔ)器方面,以含Si量子點(diǎn)的a-SiC:H薄膜為電荷存儲(chǔ)層制備了電容存儲(chǔ)器,研究了它的充放電過程和機(jī)制。首先,以不同掃描電壓下的C-V特征曲線驗(yàn)證了Si量子點(diǎn)的電荷存儲(chǔ)行為；通過G-V曲線中電導(dǎo)峰的移動(dòng)分析了電容存儲(chǔ)器件中電荷在襯底和Si量子點(diǎn)間的轉(zhuǎn)移過程。分析表明,電荷存儲(chǔ)層中的大多數(shù)Si量子點(diǎn)的庫(kù)倫充電能大于室溫下電子的熱能,Si量子點(diǎn)具有庫(kù)倫阻塞效應(yīng)；較大尺寸的Si量子點(diǎn)具有更小的庫(kù)倫充電能,能夠俘獲兩個(gè)或者更多的電子；Si量子點(diǎn)的充放電取決于Si量子點(diǎn)與a-SiC:H基質(zhì)間的勢(shì)壘以及Si量子點(diǎn)的尺寸和量子點(diǎn)間的距離,較大尺寸的Si量子點(diǎn)和較低的勢(shì)壘能增強(qiáng)Si量子點(diǎn)的電荷存儲(chǔ)效應(yīng),即增大存儲(chǔ)器的存儲(chǔ)窗口。
[Abstract]:Silicon quantum dots are widely used in photoelectron and microelectronic devices because of their unique quantum effects. The process of preparing silicon quantum dots by plasma enhanced chemical vapor deposition and thermal annealing is described in this paper. The Si rich SiC:H films prepared under different annealing conditions were characterized and analyzed. The existence of silicon quantum dots in the annealed samples was proved. The Si-rich a-SiC: h / c Si heterostructure was prepared by changing the annealing conditions. The relationship between the microstructure evolution in Si-rich a-sic: h thin film and the energy band distribution at the Si-rich a-sic: h / c-Si heterointerface is studied. The adjustment of the band order of the Si-rich a-SiC: h / c-Si heterointerface is realized. The energy band distribution at the Si-rich a-SiC: h / c Si heterointerface is mainly due to the crystallinity of the quantum dots in the film. The effects of the size of quantum dots and the ratio of Si to SiC quantum dots, The heterojunction band regulation can improve the interfacial transport characteristics of carriers and the performance of heterojunction devices. In order to explore the application prospect of silicon quantum dots in heterojunction energy band regulation, The influence of the energy band distribution at the interface of silicon based heterojunction solar cells on the interfacial transport performance is studied by simulation. Finally, the photoelectric conversion efficiency of the silicon based heterojunction solar cells is 27.377.In addition, the open circuit voltage is 805.5 MV, the short-circuit current density is 41.85 Ma / cm ~ 2, and the filling factor is 81.2%. Si-based heterojunction solar cells were prepared by using boron doped ZnO- BZO thin films prepared by MOCVD process as transparent electrode. The effects of B _ 2H _ 6 flow rate and substrate temperature on the microstructure, optical and electrical properties of BZO thin films were investigated. When the flow rate of B2H6 is about 10 sccm and the bottom temperature is about 170 鈩，

本文編號(hào)：1623749