Low dimensional silicon for integrated optoelectronics

In contrast to bulk silicon, which is an indirect gap semiconductor, with very low efficiency in radiation emission, low dimensional silicon structures (quantum dots or wires) can emit light with very high efficiency at room temperature. The best known form of low dimensional silicon is porous silicon but other materials of low dimensional silicon, in the form of nanocrystallites or nanowires within insulating matrices, can be fabricated. Their application in silicon based optoelectronics is a challenging one. In this respect, both materials and fabrication techniques need to be compatible with the existing silicon technology. In this paper, the fabrication and properties of low dimensional silicon (nanowires in the form of silicon nanopillars on bulk crystalline silicon and nanocrystallites deposited on thin SiO₂ layers) will be discussed