Fabrication and electrical characterization of Al/DNA-CTMA/p-type a-Si:H photodiode based on DNA-CTMA biomaterial

In this work, a deoxyribonucleic acid-cetyltrimethylammonium chloride (DNA-CTMA) biomaterial based p-type hydrogenated amorphous silicon (a-Si:H) photodiode (PD) is fabricated and its electrical characteristics are investigated. The Al/DNA-CTMA/p-type a-Si:H PD parameters are studied using current-voltage (I-V), capacitancevoltage-frequency (C-V-f) and conductance-voltage-frequency (G/ω-V-f) measurements. The barrier height and the ideality factor of the diode are found to be 0.78 eV and 1.9, respectively. The electrical and photoconductivity properties of the diode are analyzed by using dark I-V and transient photocurrent techniques. The C-V-f and G/ω-V-f measurements indicate that the capacitance and conductance of the diode depend on the voltage and frequency, respectively. The experimental results reveal that the decreases in capacitance and the increases in conductance with an increase in frequency can be explained on the basis of interface states (NSS). Series resistance (RS) measurements are performed on the diode and discussed here. The obtained electrical parameters confirm that the Al/DNA-CTMA/p-type a-Si:H PD can be used as an optical sensor for the development of commercial applications that are environmentally benign.