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

► 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.