Distribution of surface states based on Hill and Coleman conductance technique

Hill-Coleman’s single frequency conductance technique for the determination of surface state density has been extended upto 2 kHz. A.c. conductance (G _m) and capacitance (C _m)versus gate bias (V _G) curves were obtained at various signal frequencies. Shift of the observed peaks in theG _m versus V_G curves for different signal frequencies was utilized for the determination of surface state density at different surface potentials (φ _s). Determination of surface state density for differentφ _s values was also done by Nicollian-Goetzberger method and the results compared. Results obtained by Hill-Coleman technique compare reasonably well with those obtained by the other method.