Surface texturing-induced Interface engineering in Ag/ In2S3/B-Si heterojunctions: Morphological evolution, impedance response, and charge transport mechanisms

Abstract

The influence of In 2 S 3 /B-Si interface engineering on the structural, dielectric, impedance, and charge-transport properties of Ag/In 2 S 3 /B-Si/Al heterojunction diodes was systematically investigated. Boron-doped silicon wafers were textured using KOH/Isopropyl alcohol (IPA), Na 2 CO 3 , and Na 2 CO 3 /NaHCO 3 alkaline solutions before In 2 S 3 deposition by thermal evaporation. FE-SEM analysis revealed pronounced variations in surface morphology and pyramid structure, accompanied by reduced optical reflectance and modified interfacial characteristics. AC conductivity measurements over 50 Hz–8 MHz and 293–353 K followed Jonscher's universal power law and exhibited two distinct frequency regimes, indicating different hopping contributions. The temperature-dependent frequency exponent supported correlated barrier hopping (CBH) as the dominant transport mechanism, with low-frequency conduction mainly associated with localized states at the In 2 S 3 /B-Si interface and high-frequency conduction attributed to short-range hopping within the In 2 S 3 layer. Impedance spectroscopy further distinguished bulk and interfacial contributions and revealed a strong dependence of the interfacial resistance on the Si texturing conditions. Temperature-dependent current–voltage measurements indicated thermally activated transport and barrier inhomogeneity at the heterointerface. Overall, the results demonstrate that alkaline surface texturing provides an effective approach for tailoring interfacial and charge-transport properties in Ag/In 2 S 3 /B-Si/Al heterojunction diodes, highlighting their potential for optoelectronic and photovoltaic applications.