壊れやすい半導体材料における塑性加工を実現(Scientists Achieve Plastic Warm Metalworking in Previously Brittle Semiconductors)

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2025-05-12 中国科学院(CAS)

壊れやすい半導体材料における塑性加工を実現(Scientists Achieve Plastic Warm Metalworking in Previously Brittle Semiconductors)Warm metalworking for plastic manufacturing in brittle semiconductors. Left: Illustration and photos of warm metalworking techniques; Right-top: Experimental vs. predicted brittle-to-ductile transition temperatures; Right-bottom: Normalized power density of thermoelectric devices based on warm-metalworked films (Image by SHI Xun)

中国科学院上海硅酸塩研究所と上海交通大学の研究チームは、従来脆性とされていた無機半導体材料に対し、200℃以下の温度で塑性加工(ウォームメタルワーキング)を実現しました。これにより、Cu₂Se、Ag₂Se、Bi₉₀Sb₁₀などの材料が圧延や押出し加工に適用可能となり、最大90cmの長さまで延伸できるなど、約3000%の伸長性を示しました。加工後の薄膜は、基板不要で厚さを自在に調整でき、高い結晶性とキャリア移動度(1000~5000 cm²/V·s)を保持しています。また、研究チームは、温度依存の原子集団変位と熱振動に基づくモデルを構築し、脆性から延性への転移温度を予測することに成功しました。この技術を用いて作製された熱電デバイスは、従来のAg₂Sベースのデバイスと比較して、出力密度が約2倍(43–54 μW/cm²·K²)に向上しています。この成果は、無機半導体の柔軟電子機器やエネルギーデバイスへの応用を大きく前進させるものです。

<関連情報>

脆性半導体におけるプラスチック製造のための温金属加工 Warm metalworking for plastic manufacturing in brittle semiconductors

Zhiqiang Gao,Shiqi Yang,Yupeng Ma,Tian-Ran Wei,Xiaohui Chen,Wenwen Zheng,Pengfei Qiu,Xiaoqin Zeng,Lidong Chen & Xun Shi
Nature Materials  Published:28 April 2025
DOI:https://doi.org/10.1038/s41563-025-02223-9

Abstract

Semiconductors are the core of modern electronics1. Because of their brittleness, semiconductors are usually processed by the complicated techniques of sputtering or deposition2,3,4, instead of the effective and versatile metalworking methods like rolling, extrusion and pressing used with metals5. Here we show that brittle semiconductors can be plastically manufactured with an extensibility as large as ~3,000% using warm metalworking, that is, plastic manufacturing at slightly elevated temperatures (empirically below 500 K). Many bulk brittle semiconductors, such as Cu2Se, Ag2Se and Bi90Sb10, can be processed like metals below 400–500 K into free-standing, large and high-quality films with a thickness from the macro-scale to the micrometre scale. A model based on temperature-dependent collective atomic displacement and thermal vibration is proposed to explain the superior plasticity. The warm-metalworked films can retain the excellent and tunable physical properties of the bulk versions, such as a high carrier mobility up to ~5,000 cm2 V−1 s−1 and tunable electrical conductivities over six orders of magnitude by adjusting the chemical composition. A case study in film thermoelectric devices demonstrates ultra-high normalized output power densities of 43–54 μW cm−2 K−2. This work suggests that brittle semiconductors can be manufactured by warm metalworking for applications in various electronics.

0705金属加工
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