Influence of boron-doped Si cap layer on the photoluminescence of β-FeSi2 particles embedded in Si matrix

Abstract

The influence of a boron-doped silicon cap layer on the photoluminescence (PL) of β-FeSi2 particles embedded in a silicon p–n junction is investigated. PL is found to improve significantly by optimizing silicon growth temperature and boron concentration. Surface morphology is also analyzed by atomic force microscopy. Dislocations and point defects are found to be generated by oxygen incorporated into the heavily boron-doped silicon layer during the 14 h of thermal annealing at 900 °C, and are suggested to be responsible for the quenching of the 1.53 μm PL.

Photoluminescence decay time and electroluminescence of p-Si∕β-FeSi2 particles∕n-Si and p-Si∕β-FeSi2 film∕n-Si double-heterostructures light-emitting diodes grown by molecular-beam epitaxy

“…Details of the growth procedure were described in our previous report. 29 Samples were prepared as summarized in Table I.…”

“…That is why we excluded sample B for this measurement. In order to form a p + -Si layer using HBO 2 , at least 700°C is necessary; 29 however, the 8-nmthick ␤-FeSi 2 in sample B agglomerates into ␤-FeSi 2 particles at this temperature. We have not yet succeeded in forming p + -Si layers in sample B while preventing the agglomeration of ␤-FeSi 2 layers.…”

Room-temperature electroluminescence of a Si-based p-i-n diode with β-FeSi2 particles embedded in the intrinsic silicon

“…Details of the growth procedure have been described previously. 9,10 Samples were grown using an ion-pumped molecular beam epitaxy system equipped with Si and Fe electron gun evaporation sources. Initially, 250 nm unintentionally doped Si ͑lightly p-type Si͒ buffer layer was deposited on the n-type epitaxial Si͑001͒ substrate, which is thermally cleaned at 850°C.…”

Growth and Characterization of Si-Based Light-Emitting Diode with β-FeSi2-Particles/Si Multilayered Active Region by Molecular Beam Epitaxy

“…Consequently, a 0.3-mm-thick undoped Si layer was grown by MBE at 500 C. 4) For a double-layered structure, another 10-nm-thick [100]-oriented -FeSi 2 epilayer was grown on the undoped Si layer by RDE at 470 C, followed by annealing at 850 C and a subsequent overgrowth of a 0.3-mm-thick undoped Si layer at 500 C. This process was repeated for a triple-layered structure. For EL measurements, a boron-doped p þ -Si cap layer with a doping concentration of approximately 1:0 Â 10 18 cm À3 was grown at 700 C on top of the undoped Si layer 18) for the single-and double-layered structures. Unfortunately, we did not prepare triple-layered LEDs due to a problem with the growth chamber.…”