Spin-on doping of porous silicon and its effect on photoluminescence and transport characteristics

We have investigated a novel way to dope porous Si layers with (B) and/or (P) using the spin-on doping technique. Under certain conditions, pore filling by the dopant solution was measured to be near 90%–95% leading to a homogeneous coverage of the porous skeleton. Near two orders of magnitude decrease in diode resistance was achievable following rapid thermal activation in a ${\mathrm{N}}_{\mathrm{2}}$ atmosphere of B only or B+P double doped porous Si. Photoluminescence (PL) intensities observed in B+P double doped porous layers were significant. Relative to as-prepared samples, the PL intensities of double doped samples were weaker for porous Si on $n$ -type and stronger for porous Si formed on $p$ -type Si. In both cases, the PL magnitudes after double doping were comparable.