Localisation of excitation in InGaN epilayers

Vyacheslav Kachkanov (1) , Kevin Peter O'Donnell (2) , Sergio Pereira (3) , Robert Martin (1)

1 SUPA Physics
2 SUPA Physics
3 Departamento de Fisica [Aveiro]

Energy scalability of the excitation-emission spectra of InGaN epilayers, quantum wells and light emitting diodes provided indirect evidence for a fundamental common cause of the remarkable optical properties of this commercially important semiconductor alloy. Phase segregation on the nano-scale (accidental quantum dot formation) has generally been accepted as the mechanism of the spectral energy scaling (O'Donnell et al, PRL 82, 237 (1999)). Recently, however, the downsizing of the InN bandgap, from 2 to about 1 eV, has prompted a re-examination of the observations. Here, we present new structural evidence of InGaN nanostructure, obtained from a comparative analysis of Ga and In K-edge EXAFS (Extended X-ray Absorption Fine Structure) of a wide range of InxGa1-xN epilayer samples. The mean In-Ga and Ga-In next-nearest-neighbour (NNN) separations are found to be unequal in length for InN-poor (0.1

Mots clés: Physical Sciences

Vyacheslav Kachkanov, Kevin Peter O'Donnell, Sergio Pereira, Robert Martin. Localisation of excitation in InGaN epilayers. Philosophical Magazine, 2007, 87 (13), pp.1999-2017. ⟨10.1080/14786430701342164⟩. ⟨hal-00513828⟩