Efficient n-Type Surface Doping in Diamond

Abstract

Conventional doping in diamond is challenging for its application in electronic devices, which could be overcome by an alternative method of surface-transfer doping. In this study, efficient surface n-type conductivity is obtained on the N-terminated diamond surface doped with decamethylcobaltocene (DMC) and cobaltocene (CoCp2) molecules having low ionization energy values by first-principles calculation. By the surface-transfer doping mechanism, electrons are transferred from the dopants to diamond, and then electron accumulation occurs on the diamond surface. For DMC- and CoCp2-doped diamond surfaces, the areal electron density values are 4.822 × 1013 and 4.519 × 1013 cm–2, and the carrier mobility values are 357 and 108 cm2 V–1 s–1 at 298 K, respectively. Moreover, after DMC and CoCp2 molecular adsorption, the optical absorption coefficient increases in the visible region. This study will promote investigations for two-dimensional electron gas on the diamond surface.