Direct band gap opening in graphene by BN doping: Ab initio calculations

Ab-initio calculations on graphene doped with boron nitride (BN) nanoribbons and patches show opening of a band gap in all cases. The smallest width of graphene in these hybrid layers controls the band gap that varies slowly around similar to 0.75 eV when the width of graphene region is in the range of 2 to 5 zigzag chains. Most interestingly the band gap is direct in all the cases we have studied and nearly the same for different doping if the smallest graphene width is the same. These results show the possibility of ultrathin hybrid semiconductor graphene with band gap similar to silicon and an additional attractive feature that it is direct.