OPTICAL AND ELECTRICAL-PROPERTIES OF NANO-CRYSTALLINE GAN THIN-FILMS AND THEIR APPLICATION FOR THIN-FILM-TRANSISTOR

Application of a nano-crystalline GaN to thin-film transistors is demo nstrated. Two types of TFT structures, a bottom gate type and a top ga te type, are examined. The held effect mobilities of the former and th e latter type TFTs were 6 x 10(-2) and 19 cm(2)/V s: respectively. The re results are explained by the high-volume fraction of nano-crystal a nd the small deep gap state density at the free surface of nano-crysta lline films from experimental results of structural, optical and elect rical measurements. It is demonstrated that the nc-GaN TFT performance is not influenced by white light irradiation of 1.2 mW/cm(2) except f or a slight increase in the off-current. (C) 1998 Elsevier Science B.V . All rights reserved.