Low-temperature direct growth for low dislocation density in III-V on Si towards high-efficiency III-V/Si tandem solar cells

Si tandem solar cells are attractive for new applications such as photovoltaic-powered vehicles because of their high-efficiency and low-cost potential. In particular, III-V/Si tandem solar cells have higher efficiency potential compared to perovskite/Si and other Si tandem solar cells. Although the direct growth of III-V layers on Si is very attractive for cost reduction and simple processing potential, high-quality growth of the III-V thin-film layer on Si is necessary. The paper discusses the effectiveness of the low-temperature growth of III-V layer on Si substrates for realizing low-density dislocations on Si substrates. Low dislocation density of less than 3 × 105 cm−2 in GaAs-on-Si by low-temperature growth is demonstrated in this study. According to our analytical results, this low dislocation density shows high potential efficiency of more than 33% and 38% for III-V/Si 2-junction and 3-junction tandem solar cells, respectively.