High carrier mobility of diamond (100) enabled by surface modification using doped hexagonal boron nitride

Diamond with high carrier mobility is desirable for the next generation electronic devices for high-speed, high-power, and radio frequency applications, which, however, is difficult to achieve due to the trapped charges at the dielectric/diamond interface. Here, we report the improved carrier mobility of diamond(100) enabled by surface modification with two-dimensional doped hexagonal boron nitride (h-BN). The energetically optimized structures of diamond(100)/h-BN heterojunctions doped with Mg or Si at different atomic layer positions are studied through first principles calculations. The interaction between impurity atoms in h-BN to the diamond surface is particularly investigated according to the doping position. Surprisingly, when Mg doping at the interfacial layer of h-BN/diamond, specifically in the second h-BN layer from the interface, a considerably high hole mobility (∼2645 cm2/Vs) is achieved, in strong contrast to the same doping with Si. The mechanism of interfacial doping enhancement in hole mobility is specially studied. The results of this work provide potential routes for developing high mobility diamond-based electronic devices through surface modifications via h-BN.