GaNAs基超晶格太阳电池的分子束外延生长与器件特性

MBE Growth of GaNAs-based Superlattice Solar Cells and Device Properties

采用分子束外延(MBE)生长技术生长了周期厚度不同的1 e V吸收带边的Ga N0.03As0.97/In0.09Ga0.91As应变补偿短周期超晶格(SPSL)。高分辨率X射线衍射(HRXRD)测量结果显示,当周期厚度从6 nm增加到20 nm时,超晶格的结晶质量明显改善。然而,当周期厚度继续增加时,超晶格品质劣化。对超晶格周期良好的样品通过退火优化,获得了具有低温光致发光现象的高含N量Ga NAs/In Ga As超晶格,吸收带边位于1 e V附近。使用10个周期的Ga NAs/In Ga As超晶格(10 nm/10 nm)和Ga As组成的p-i-n太阳电池的短路电流达到10.23 m A/cm2。经聚光测试获得的饱和电流密度、二极管理想因子与由电池暗态电流-电压曲线得到的结果一致。

Period thickness-dependent GaNAs/InGaAs short-period superlattice and solar cells with an absorption edge of around 1 eV were grown by MBE. High-resolution X-ray diffraction ( HRXRD) measurements indicate that the crystalline quality of SPSL is improved while the period thickness increases from 6 nm to 20 nm. However, when the period further rises, the period repeat-ability and interface quality of SPSL degrade. By using a proper thickness and optimization of ther-mal annealing, good optical properties of SPSL with higher N content in the superlattice are achieved. The samples show an absorption edge of around 1 eV. The p-i-n solar cell using the opti-mized SPSL as the active region was fabricated. The short-circuit current density of the device rea-ches 10. 23 mA/cm2 . The ideality factor extrapolated by concentrator test of the p-i-n soalr cells is in good agreement with that of J-V curves under darkness.