|
We have analyzed the electronic properties of defects on GaAs(110) by scanning tunneling microscopy (STM), scanning tunneling spectroscopy (STS), electronic structure simulations based on density functional theory (DFT) with HSE03 functionals [1,2], and STM/STS simulations [3]. We find that the HSE03 functionals significantly improve the description of the bandgap of the semiconductor surface, in line with recent bulk simulations [2]. Interestingly, the bandgap of a highly n-doped surface is nearly equal to the bandgap obtained with standard DFT functionals. It can be inferred from this result that the doping may in some cases actually improve the agreement between electronic structure simulations and experiments, While for a non-doped system the bandgap in DFT simulations is generally too small, it agrees with the experiments for a high doping level. We also find that the appearance and the signature in spectroscopy experiments of defect states like Ga-vacancies on GaAs(110) is significantly changed by the doping level of the crystal. |