This study pioneers the use of CuInGaSe2, a quaternary alloy, in Schottky barrier diodes, beyond its traditional application in solar cells, highlighting its potential in sustainable energy technologies such as supercapacitors. We delve into its unique electrical and dielectric characteristics by introducing CuInGaSe2 into the Schottky barrier diode device, synthesized via an innovative liquid phase epitaxy on silicon substrates. Our investigation into the structural, electrical, and dielectric properties reveals the alloy's exceptional capacitance behavior, which transitions from positive to negative with varying frequency. It takes negative values at a frequency of 12 900 Hz and a temperature of 300 K. In comparison, at a frequency of 1216 Hz, all curves take negative and positive values, demonstrating significant promise for enhancing the efficiency and sustainability of energy storage solutions. These findings contribute to the advancement of supercapacitor production and underscore the broader applicability of CuInGaSe2 in promoting sustainable energy technologies.