ABSTRACTThe ion bombardment effects of low energy molecular nitrogen ions (100eV) on GaAs have been investigated using in-situ polar angle dependent X-ray photoelectron spectroscopy. It was found that arsenic and gallium nitrides were formed as a result of the nitrogen ion bombardment. The ion bombardment also caused a depletion of arsenic in the near surface region. For example, with a dose of 6×1015 cm-2 of nitrogen molecular ions at 100eV, the surface structure can be described approximately as 1.5nm of Ga0.67A0.33N on GaAs. The ion bombardment moves the Fermi levels of both n-type and p-type GaAs to mid-gap. Heating the ion bombarded samples in a vacuum chamber to 500°C desorbs all arsenic nitrides but most of the gallium nitrides remain on the surface. The Fermi levels of both n-type and p-type are then stablized at about 0.4eV from the valence band maximum. A surface type-inversion of the n-type substrate is therefore induced by the nitrogen-ionbombardment/annealing treatment.
From megahertz to terahertz qubits encoded in molecular ions: theoretical analysis of dipole-forbidden spectroscopic transitions in N2+
