Electrical Characteristics of Cadmium Sulfide/4-Amino-2-Methyl-Quinoline Heterojunction Structure

Abstract

We fabricated a heterojunction structure composed of n-CdS and p-C10H10N2 films. The CdS film was prepared using the CBD method, while the C10H10N2 film was prepared using the spin coating method. Later, we performed the current-voltage (I-V) measurement of this PN diode which we made using Keithley 2400 sourcemeter. As can be seen from the logI-V diagram, this heterojunction structure exhibits rectifying properties. Using traditional methods, an ideality factor (n) of 1.93 and a barrier height value (Φb) of 0.79 eV were determined. An ideality factor of more than one indicates non-ideal I-V behavior in the CdS/C10H10N2 heterojunction diode formed. The interface layer, interface states and series resistance are some of the causes of this deviation. Moreover, Cheung's functions and a modified Norde function were used to determine the diode parameters, such as ideality factor, barrier height, and series resistance. With the Cheung method, n=4.33, series resistance (RS)=168.65 kΩ and Φb=0.62 eV were found. Additionally, RS=686.08 kΩ and Φb=0.78 eV were found by the Norde method. Consistent barrier height values were found in all methods through comparison, suggesting compatibility. However, it was discovered that the series resistance values yielded by the Norde function exceeded those obtained by the Cheung functions.