TFT's and Solar Cells on Flexible Substrates Using Microwave-Deposited Silicon

使用微波沉积硅的柔性基板上的 TFT 和太阳能电池

• 批准号: 0324893
• 负责人: Wayne Anderson
• 金额: $ 25.34万
• 依托单位: SUNY at Buffalo
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-01 至 2007-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0324893&HistoricalAwards=false
• 关键词: TFT; Solar; Cells; Flexible; Substrates

High-quality nanocrystalline silicon (nc-Si) films will be deposited by microwave electron cyclotron resonance (MECR) chemical vapor deposition with application to thin film transistors (TFT's) and heterojunction solar cells. An in-situ residual gas analyzer (RGA) will monitor the process and achieve reproducible conditions. Recent work has given a field effect mobility of amorphous (a-Si:H) films of 3 cm2/V-s compared to the usual values of 1 cm2/V-s and over 15 cm2/V-s has been achieved so far with nc-Si films. Hydrogen dilution (HD) and photon assist (PA) during deposition permit lower substrate temperatures during deposition. The MECR process places the substrate away from the plasma to avoid plasma damage. Thus far, TFT's have been quite good using oxide-coated Si, quartz, glass and plastic substrates. The process transfers readily to a variety of substrates with little loss in performance.Concerning intellectual merit, the MECR process with HD and PA will be devoted to achieve high quality Si films at temperatures 250 C on lower cost plastics. Oxide formation for the gate of TFT's will be done at temperatures 200 C. Film analysis will utilize high resolution transmission electron microscopy, atomic force microscopy, secondary ion mass spectroscopy and other methods. Grazing incidence X-ray scattering will evaluate substrate-film interfaces to minimize carrier recombination at hetero-interfaces and results correlated with deep level transient spectroscopy. Smaller gate dimensions , using e-beam pattern generation at Cornell University and a new system to be installed in Buffalo, will give much better values of field effect mobility and better devices. The all Si heterojunction solar cell will utilize MECR-deposited a-Si:H and nc-Si on a Si wafer or thin film to achieve much higher currents than with normal cells due to the bandgap difference in the layers. Past efficiency values of 10.5% should be increased to 15% by improved films interfaces. Concerning broader impact issues, the graduate student will interface with another graduate student supported on a NASA Space Grant and another supported part-time as a teaching assistant. An undergraduate student and a minority high school student, with support from the University's BEAM program, will also work on the project. Minorities and women will be encouraged to participate. Research tasks and educational courses will be linked to mutually benefit from the project. This work will also interface with Cornell University for nano-fabrication, Brookhaven for GIXS work , the team in Buffalo setting up the new e-beam system, NREL for materials and photovoltaic measurements, SUNY at Stony Brook for modeling and technical expertise, and Taitech, Inc. for measurements. Technology transfer mechanisms are in place at the university.

采用微波电子回旋共振（MECR）化学气相沉积技术制备高质量的纳米晶硅（nc-Si）薄膜，并应用于薄膜晶体管（TFT）和异质结太阳能电池。现场残余气体分析仪（RGA）将监控过程并达到可重现的条件。最近的研究表明，非晶（a- si:H）薄膜的场效应迁移率为3 cm2/V-s，而通常的值为1 cm2/V-s，迄今为止，nc-Si薄膜的迁移率已超过15 cm2/V-s。沉积过程中的氢稀释（HD）和光子辅助（PA）允许在沉积过程中降低衬底温度。MECR工艺将基板置于远离等离子体的地方，以避免等离子体损伤。到目前为止，TFT在使用氧化涂层硅、石英、玻璃和塑料衬底方面表现相当好。该工艺很容易转移到各种基材上，性能损失很小。在知识价值方面，HD和PA的MECR工艺将致力于在250℃的温度下在低成本塑料上获得高质量的Si膜。薄膜分析将采用高分辨率透射电子显微镜、原子力显微镜、二次离子质谱等方法。掠入射x射线散射将评估衬底-膜界面，以减少异质界面的载流子复合，结果与深能级瞬态光谱相关。更小的栅极尺寸，使用康奈尔大学的电子束模式生成和布法罗安装的新系统，将提供更好的场效应迁移率值和更好的设备。全硅异质结太阳能电池将利用mecr沉积在硅晶片或薄膜上的a-Si:H和nc-Si，由于层间的带隙差异，可以获得比普通电池高得多的电流。通过改进薄膜界面，将过去10.5%的效率值提高到15%。关于更广泛的影响问题，研究生将与另一名获得NASA太空补助金的研究生和另一名兼职助教进行交流。在该大学BEAM项目的支持下，一名本科生和一名少数族裔高中生也将参与该项目。将鼓励少数民族和妇女参与。研究任务和教育课程将相互联系，从项目中受益。这项工作还将与康奈尔大学进行纳米制造，布鲁克海文进行GIXS工作，布法罗团队建立新的电子束系统，NREL进行材料和光伏测量，纽约州立大学石溪分校进行建模和技术专业知识，以及Taitech公司进行测量。该大学已经建立了技术转让机制。