Year: 2026
Type: preprint
Abstract: Semiconductor heteroassembly can integrate complementary properties through nanoscale interfaces, but structural integration alone does not necessarily yield optoelectronic functionality. Here, we demonstrate an optoelectronically active Cu2S/Co9S8 heteroassembly for photodetection, obtained through higher-temperature nucleation and growth conditions that may promote enhanced crystallization and structural ordering of Co9S8. Structural characterization reveals crystalline Cu2S nanostructures decorated with dense 3–5 nm Co9S8 nanocrystallites, providing extensive interfacial contact. HRTEM, electron diffraction, XRD, and elemental mapping confirm the coexistence and spatial integration of the two phases. Controlled antisolvent processing reduces residual organic content and enables formation of uniform films. A vertical Cu2S/Co9S8/n-Si device exhibits broadband photoresponse with rise and fall times of 2.7 and 2.3 s, respectively. At 2 V bias, the device achieves a responsivity of 1.93 mA W-1 and a shot-noise-limited detectivity of 6.3 × 107 Jones. The bias-dependent response is attributed to field-assisted photocarrier separation and extraction, with the Cu2S/n-Si junction and Cu2S/Co9S8 interfaces influencing carrier transport. These results highlight the combined importance of structural ordering and interfacial architecture in converting nanoscale heteroassembly into functional optoelectronic devices.
Source: ChemRxiv
Author: Biman Jana
Institution: Indian Institute of Science Bangalore
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7221449291