Fabrication of heterojunction crystalline Si solar cells with BaSi2 thin films prepared by a two-step evaporation method

We have fabricated p-type BaSi2 (p-BaSi2)/n-type crystalline Si (n-c-Si) heterojunction solar cells using thermal evaporation. To control the defect around the heterointerface, samples were fabricated by two methods using different current profiles during evaporation. The one-step method was designed to avoid supplying Ba-rich vapor, and the two-step method was designed to intentionally introduce Ba-rich vapor at the first step. Deep-level transient spectroscopy measurements revealed that defect densities in the n-c-Si side were almost the same for both samples. Open-circuit voltage (V (oc)) was successfully improved from 319 to 463 mV by the two-step method. This may be due to the increase of carrier density in p-BaSi2 prepared using a two-step method. As a result of optimization, the conversion efficiency of 6.23% was achieved by the heterojunction solar cells.

Automated summary

P-type BaSi2/n-type crystalline Si heterojunction solar cells were fabricated using thermal evaporation, with samples prepared by two different methods to control defect densities around the heterointerface. The two-step method successfully improved the open-circuit voltage from 319 to 463 mV, potentially due to increased carrier density in p-BaSi2. Through optimization, the conversion efficiency of the heterojunction solar cells reached 6.23%.