Hole subband in p-type channel of semiconductor heterostructures

Based on the characteristics of semiconductor surface capacitance, an experimental model is presented for evaluating the hole subband structures in the p-type channel of semiconductor heterostructures. For an n-type InSb metal-oxide-semiconductor sample, the capacitance-voltage spectroscopy is measured and the hole subband structure is derived with using the model presented. The result shows that the Fermi level is always pinned near the bottom of the hole subband, which is attributed to the large density of states of the hole subband. Relevant parameters are also obtained for the hole subband including the subband energy, Fermi level, inversion layer width, and depletion layer width, etc.