Synthesis of flowerlike Si nanostructures on Si substrates

The flowerlike Si nanostructures rooted on Si(111) substrates were synthesized using MnCl2 and Si sources by chemical vapor deposition (CVD). These nanostructures consist of thin Si(111) sheets with a thickness of about 100 nm or less. Their structural properties were clarified in detail by transmission electron microscopy (TEM). Their photoluminescence (PL) measurements revealed that the band edge emission of Si clearly appeared, and dislocation-related emissions were hardly observed. PL spectra showed a thermally stimulated emission with an activation energy of 19 meV in the temperature range between 100 and 200 K. These results suggest that exciton and/or carrier trap centers exist inside the flowerlike Si nanostructures. It is expected that the nanostructures can be used for the improvement of energy devices.