On thermal and optical sensor applications of chitosan molecule in the Co/Chitosan/p-Si hybrid heterojunction design

Fabrication and Characterization of Eco-Friendly Thin Films as Potential Optical Absorbers for Efficient Multi-Functional Opto-(Electronic) and Solar Cell Applications

“…Otherwise, all the fabricated devices show a rectification behavior, where the highest rectification ratio (RR~137) under dark conditions is observed in the case of the Ag/Cs-MV/p-Si device, as shown in Figure S8a (Supporting Information). The difference in the obtained low values of RR compared to the previously reported values of Co/chitosan/p-Si [13] may be ascribed to the difference between the work function of the utilized electrodes [38,49]. Following is the thermionic emission model for estimating the microelectronic parameters of the designed non-ideal junctions (n > 1) of series resistance, R s , where the current-voltage-temperature (I-V-T) is represented as follows [34,38,39,46]:…”

“…It is well known that the controllability of the barrier height depends on the characteristics of the inserted organic film between the metal/semiconductor interface, such as its HOMO and LUMO energetic position, and their position relative to semiconductor electron affinity and electrode work function. The obtained values of Φ B0 of all the fabricated devices are higher than those previously recorded for Au/Cs/n-Si (~0.73 eV [23]) and Co/Cs/p-Si (~0.68 eV [13]) but lower than those estimated for Ag/Cs/n-Si (~0.94 eV [22] and Ag/Cs/n-Si (~0.88 eV [12]). The values of shunt resistance, R sh , and series resistance, R s , of the fabricated devices were estimated from the junction's resistance, R j , and plotted, as shown in Figure S8e,f (Supporting Information), respectively.…”

“…The nonideality of the fabricated devices may be rationalized because of the formation of a native oxide layer between Si and the spin-coated chitosan film that develops sufficient series resistance in addition to the hypothetical consequences of the existence of variable heights in the Schottky barrier height (SBH) [12][13][14]38,39,46,50]. In addition, the developed interface states density between the chitosan and p-Si as well as the image forces and tunneling mechanism of charges may contribute to the nonideality of the present devices [12][13][14]38,39,46,50]. Likewise, the dark reverse saturation current and barrier height were estimated and plotted, as shown in Figure S8c,d (Supporting Information), respectively.…”

“…On the other side, chitosan has been exploited in many electronic and optoelectronic applications, such as photodiodes [12], thermal sensors [13], Schottky barrier modifier [13,14], resistive random-access memory (RRAM) [15,16], light-emitting diodes [17], humidity sensors [18,19], modulators [20], and optical waveguides, where the lower-molecular-weight chitosan achieved lower loss than that of the higher molecular weight [21]. Additionally, chitosan possessed unique photochromic features [22] and corrosion inhibition [23].…”