Room-temperature below bulk-Si band gap photoluminescence from P and B co-doped and compensated Si nanocrystals with narrow size distributions

Thin films consisting of the layers of phosphorus (P) and boron (B) co-doped Si nanocrystals (Si-ncs) and glass spacer layers were prepared and their photoluminescence properties were studied. Cross-sectional TEM observations revealed the growth of Si-ncs with narrow size distributions. The samples exhibited PL below the band gap energy of bulk Si crystal at room temperature. The low-energy PL is considered to arise from the transitions between donor and acceptor states in compensated Si-ncs. The successful formation of narrow size distribution co-doped Si nanocrystals promotes the study of the optical properties of compensated Si nanocrystals. ► P and B co-doped Si nanocrystals (Si-ncs) with narrow size distribution are produced. ► The co-doped and compensated Si-ncs exhibit PL below bulk Si band gap at room temperature. ► The low-energy PL may arise from donor to acceptor transitions in compensated Si-ncs.