by Riko Seibo
Tokyo, Japan (SPX) Dec 17, 2025
Researchers at Chonnam Nationwide College within the Republic of Korea report {that a} nanometer scale germanium oxide layer can tackle a longstanding bottleneck in tin monosulfide skinny movie photo voltaic cells by enhancing the rear contact interface with the metallic electrode. They centered on tin monosulfide, or SnS, a non poisonous and low price absorber that makes use of earth ample components and avoids indium, gallium, and tellurium whereas providing favorable optical and digital properties for daylight harvesting in concept. In apply, measured efficiencies have lagged theoretical predictions due to structural defects, parasitic reactions, and atomic diffusion on the interface the place SnS meets the again metallic contact.
The workforce led by Professor Jaeyeong Heo and Dr Rahul Kumar Yadav designed a tool structure that inserts an extremely skinny germanium oxide, or GeOx, interlayer between the molybdenum again contact and the SnS absorber. Their research, revealed on-line in Small on September 19 2025, describes how this interface engineering technique targets deep stage defects and undesirable chemical phases that kind throughout excessive temperature processing of standard SnS cells.
To manufacture the GeOx layer, the researchers used a vapor transport deposition course of that first deposits a really skinny germanium movie after which depends on its pure oxidation to kind a managed oxide with a thickness of about 7 nanometers. This strategy is suitable with scalable, business oriented skinny movie processing. “Regardless of its nanoscale thickness, this interlayer addresses a number of long-standing challenges directly,” explains Prof. Heo. “It suppresses dangerous deep-level defects, blocks undesirable sodium diffusion, and prevents the formation of resistive molybdenum disulfide phases throughout high-temperature fabrication.”
By stabilizing the rear interface, the GeOx layer improves the microstructure of the SnS absorber, yielding bigger and extra uniform grains that facilitate cost transport. The authors report enhanced cost assortment and decrease electrical losses, which collectively elevate the general system efficiency. In quantitative phrases, the ability conversion effectivity elevated from 3.71% in customary units with out the interlayer to 4.81% when the optimized GeOx passivation was applied, one of many highest efficiencies reported for vapor deposited SnS primarily based photo voltaic cells.
The work additionally highlights broader implications of exact management over metallic semiconductor interfaces past photovoltaic units. The researchers be aware that comparable interface optimization can affect contact resistance and switching habits in skinny movie transistors, power conversion efficiency in thermoelectric modules, cost switch and detection sensitivity in sensors, mechanical reliability in versatile electronics, and operation of photodetectors and reminiscence units. “Throughout all these purposes, mastering the metallic/semiconductor interface stays central to advancing next-generation units,” says Prof. Heo. “We imagine that this work will open new avenues for analysis, contributing to the event of superior photo voltaic cells and different key applied sciences.”
Associated Hyperlinks
Chonnam National University
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