No abstract

Luminescence peak energy of amorphous hydrogenated silicon (a‐Si:H) increases with excitation energy in the Urbach tail and in the higher excitation energy range the peak energy is constant. The excitation energy at which the peak energy turns from increase to constant is shown to be understood as the hopping‐gap. The hopping‐gap decreases with temperature as in the case of the optical bandgap. Furthermore, it is discussed by comparing with the luminescence in porous Si that the luminescence in a‐Si:H may be due to the radiative recombination of electron‐hole pairs in hydrogen‐free Si nanostructures. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)