Abstract
Metal‐oxide‐semiconductor (MOS) capacitors were constructed on p‐type GaAs anodized in a tartaric acid‐water‐glycol solution at room temperature, and capacitance‐voltage measurements were made on them from the quasistatic regime to 150 MHz. The data thus obtained indicate that the zero‐bias surface potential is 0.59 V, that the total surface potential excursion is limited to ∼0.45 V, and that neither flatband nor inversion were achievable. The minimum in surface‐state density was ∼4×1012 cm−2 eV−1.