硅基CeO2薄膜电致发光器件的制备与研究

Preparing a silicon based high efficient light emitter which can be monolithically integrated in the chip is one of most essential questions in Silicon-based optoelectronics filed. Different approaches for light emitters have been studied deeply, such as Silicon-based nc-Si devices, III-V semiconductor devices bonding on Silicon wafer and rare-earth-ions-doped in SiO2 films which deposited on silicon. However, it is still hard for these devices to obtain both high luminescence efficiency and good compatibility with CMOS technology..CeO2, one kind of rare earth oxides, is expected to deposit on Silicon wafer to take place SiO2 matrix in this project. The silicon-based CeO2 films devices will be more efficient and much lower threshold voltage than that of SiO2 due to its' higher Solid Solubility of rare earth ions and excellent direct band-gap feature. Furthermore, it is beneficial to obtain high quality epitaxial films due to its' excellent lattice matching with Si wafer. In the project, CeO2 epitaxial layers will be deposited on Si wafer, the role of Ce3+ ions in photoluminescence and electroluminescence of CeO2 films devices will be researched by verifying film thickness, annealing atmosphere, annealing temperature and so on. In order to improve the EL efficiency of these devices, the method of decrease conductivity caused by Oxygen vacancy will also be studied. Our further research will refer to Rare-earth-ions-doped CeO2 films so that different wavelength EL devices could be made.

制备高效的硅基光源仍是当前硅基光电集成领域的核心研究方向之一，这就要求发光材料既有较高的发光效率又能与CMOS工艺兼容。无论是硅基nc-Si发光器件还是硅片键合III-V族半导体器件，又或是稀土离子掺杂硅基SiO2薄膜发光器件均难实现两者兼顾。.本项目拟引入稀土氧化物CeO2取代绝缘基质SiO2制备硅基稀土发光器件，由于CeO2兼具稀土发光材料与半导体材料的双重特性，不但可以增大其它稀土离子在薄膜中的固溶度，提高器件的发光效率，而且可以降低器件工作电压。另外CeO2与单晶Si晶格匹配度低，不存在兼容性问题。本项目拟在单晶Si衬底上外延生长CeO2薄膜，通过控制薄膜厚度、退火温度、退火氛围等优化器件结构，研究Ce3+离子在CeO2薄膜光致发光与电致发光中的作用。通过抑制薄膜中的氧空位导电，制备出高效的硅基CeO2薄膜电致发光器件，并探索掺杂不同稀土离子以获得不同波长的硅基电致发光器件的方法。

制备高效的硅基光源仍是当前硅基光电集成领域的核心研究方向之一，硅基光源要求发光材料既有较高的发光效率又能在晶格匹配以及工作电压方面与CMOS工艺兼容。无论是硅基nc-Si发光器件还是硅片键合III-V族半导体器件，又或是稀土离子掺杂硅基SiO2薄膜发光器件均未能很好的实现三者兼顾。.本项目引入了稀土氧化物半导体CeO2取代绝缘基质SiO2制备硅基稀土发光器件，由于CeO2兼具稀土发光材料与半导体材料的双重特性，相比于SiO2，不但增大了其它稀土离子在薄膜中的固溶度，提高了器件的发光效率；而且CeO2与单晶Si晶格失配度低，不存在兼容性问题；另外，CeO2的禁带宽度小于SiO2，有效降低了器件工作电压。我们在单晶Si衬底上外延生长CeO2薄膜，通过控制薄膜厚度、退火温度、退火氛围等优化器件结构，研究Ce3+离子在CeO2薄膜光致发光与电致发光中的作用。通过抑制薄膜中的氧空位导电，制备出了高效的硅基CeO2薄膜电致发光器件，并对CeO2薄膜进行Tb3+离子掺杂，通过能量传递制备了绿色硅基电致发光器件。