Published online by Cambridge University Press: 25 February 2011
The luminescence properties of two different modifications of siloxene are studied with photoluminescence excitation spectroscopy (PLE) und optically detected magnetic resonance (ODMR). The luminescence of as prepared siloxene, which consists of isolated silicon planes, is resonantly excited at the bandgap, indicating a direct bandstructure. The observation of Δm = ±2 transitions in ODMR shows that triplet excitons contribute to the luminescence process. In contrast, annealed siloxene consisting primarily of six-membered silicon rings shows a PLE typical of a material with an indirect bandgap. The ODMR signal of annealed siloxene and of porous silicon show the same Gaussian line with a typical width of 400 G, which can arise from strong dipolar coupling of an electron and a hole ≈ 5Å apart.