Temperature dependent negative capacitance behavior of Al/rhodamine-101/n-GaAs Schottky barrier diodes and Rs effects on the C-V and G/ω-V characteristics

In order to explain the origin of negative capacitance, we have investigated the capacitance-voltage (C-V) and conductance-voltage (G/omega-V) measurements of the Al/rhodamine-101/n-GaAs Schottky barrier diodes (SBDs) in the temperature range of 110-290 K at 1 MHz by considering the series resistance (R-s) effect. Experimental results show that the values of C and G/omega were found to be strong functions of temperature and bias voltage. A strong negative capacitance (NC) phenomenon has been observed in the C-V plot for each temperature. It is clear that, the value of NC decreases with the increasing temperature at forward bias voltage and this decrease of the NC corresponds to an increase in the conductance. Such behavior of C in the forward bias region can be explained by the loss of interface charges localized at metal/semiconductor interface because of impact ionization process. Also, the magnitude of R-s makes a negative contribution to the low temperature capacitance. In addition, the high frequency C and G/omega values measured under reverse and forward bias were corrected by eliminating the effect of R-s to obtain the real diode capacitance. (C) 2011 Elsevier B.V. All rights reserved.