Fabrication Of High Density Silicon Nano Dot Array Based On Soft Imprint Theory And The Application

One-dimensional silicon nanowires(SiNWs) have attracted intense interest inrecent years for their interesting semiconducting, mechanical, and optical properties,and promising applications in nano devices. It has been successfully used in filed-effecttransistors(FETs), bio-and chemo-sensors, integrated logic circuits, solar cells. Manymethods have been reported to fabricate SiNWs, such as vapor-liquid-solid growth,oxide-assisted growth, and solid-liquid-solid, however the SiNWs obtained by thesemethods are typically randomly oriented, so achieving high density and regular siliconnano dot array patterns is particularly important.In this paper we introduce a new method to fabricate the structure. First,nanoimprint, which is a graphic reproduction method, is discussed, we also optimize theprocess parameters, based on the matrix patterns on the glass template, we get thePMMA patterns by soft imprinting. Experimental and finite element simulation resultsshow that, soft imprinting has a better graphic reproduction accuracy and smallerresidual photoresist thickness due to the capillary force, which can lead to better fillingof polymer, so it is suitable for large area uniform replication of high density photoresiststructure. Second, by means of PMMA mask, combine with metal assisted chemicaletching(MAC) and reactive ion etching(RIE), we fabricate the silicon nano dot arraypatterns, we test and verify that SiNWs has a better light trapping properties than planarsilicon. In addition, we introduce a method to get incised trapezoidal structure based ondouble layer technology, which is suitable for lift-off process. At last, the siliconpatterns are used as the base instead of planar silicon in the fabrication of silicon solarcell, take the Au/P3HT/SiNWs/InGa solar cell as an example, we analyze theadvantages of highly ordered SiNWs in the application of solar cell.