Efficient n-Type Surface Doping in Diamond

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 x 1013 and 4.519 x 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.