Effect of illumination on the electrical characteristics of Au/n-GaP/Al and Au/Chlorophyll-a/n-GaP/Al structures

Highlights: • Chl-a film was formed on the n-GaP by spin-coating technique. • Au/n-GaP/Al and Au/chl-a/n-GaP/Al structures were fabricated. • The photocurrent in the reverse bias voltage was increased by increasing photo-illumination intensity. • The Au/n-GaP/Al and Au/chl-a/n-GaP/Al structures can be used in optoelectronic applications for the detection of light. Au/n-GaP/Al and Au/chlorophyll-a/n-GaP/Al structures were produced using n-type GaP semiconductor. A thin film layer was formed on the bright surface of the GaP semiconductor chlorophyll-a (chl-a) solution. The image of formed chl-a layer were taken by scanning electron microscope (SEM). The current voltage (I − V) measurements in dark and under illumination and capacitance–voltage (C − V) measurements in dark were taken at room temperature for the Au/n-GaP/Al and Au/ chl-a /n-GaP/Al structures. Characteristic parameters (ideality factor (IF, n), barrier height (BH) and series resistance (R_s) of these structures were calculated from ln (I) − V characteristics and Norde's functions. Similarly, for both structures, the BH, carrier concentration (N_d) in n-GaP semiconductor, diffusion potential (V_d) and Fermi energy (E_f) were calculated using C − V measurements. The photovolatic parameters of these structures were calculated from I − V measurements based on light intensity. It has been observed that chl-a thin film has changed the photovoltaic parameters of Au/n-GaP/Al structure.