新型石墨烯/氮化硼/砷化镓范德华异质结太阳能电池

项目名称： 新型石墨烯/氮化硼/砷化镓范德华异质结太阳能电池

项目编号： No.51502264

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 一般工业技术

项目作者： 李晓强

作者单位： 浙江大学

项目金额： 20万元

中文摘要： 石墨烯的费米能级可调为石墨烯/半导体异质结太阳能电池的设计带来了独特优势，已有的实验结果通过化学掺杂和电场调节证明了石墨烯费米能级调节对电池性能的巨大影响。但由于石墨烯与半导体衬底之间的电荷转移，石墨烯费米能级调节范围受到严重限制。本项目选择性能优异的砷化镓作为衬底，在石墨烯/砷化镓异质结界面上增加原子层厚度的二维六方氮化硼抑制电荷转移以获得势垒高度更高的范德华异质结，利用电学测试以及拉曼测试、瞬态PL测试研究二维氮化硼厚度对结势垒高度的影响以及对界面载流子传输与复合的影响，研究二维氮化硼厚度对石墨烯费米能级调节范围的影响，并在这些研究的基础上获得高效率的石墨烯基太阳能电池器件。本项目针对石墨烯/半导体异质结中的特殊物理，在石墨烯/氮化硼/砷化镓全新材料体系中研究范德华二维材料异质结的界面电学特性，对高性能二维材料异质结器件的设计具有重要意义。

中文关键词： 异质结；二维材料；砷化镓；太阳能电池；界面

英文摘要： Distinct from traditional Schottky diode, the barrier height of graphene/semiconductor Schottky diode is highly tunable as the Fermi level of graphene and semiconductor can be adjusted independently benefiting from the nature of van der Waals contact, the low density of energy states near Dirac point and small screening length of graphene. Reported results have proved that tuning the Fermi level of graphene can largely improve the performance of graphene/semiconductor heterostructure solar cells. While because of the charge transfer between graphene and semiconductor substrate, the range of Fermi level tuning in graphene is limited. In this project, choosing GaAs as the substrate semiconductor material, we propose inserting h-BN into the interface of graphene/GaAs to suppress the charge transfer when forming the heterojunction. The barrier height is expected to be increased by the insulating interface h-BN. The influence of the thickness of h-BN on charge transfer properties and recombination properties will be studied by electrical measurements including current-voltage and capacitance-voltage characteristics. The charge separation and collection properties will be investigated using Raman and transient PL measurements. And the Fermi level tuning effect dependent on the thickness of h-BN will be studied by employing gate effect structure. Based on these studies, we believe we can get graphene/h-BN/GaAs solar cell device with high power conversion efficiency. The results obtained in this project are very important for high performance two-dimensional materials based device design.

英文关键词： Heterostructure;Two-dimensional materials;GaAs;Solar cell;Interface