Effect of transport agent boron triiodide on the synthesis and crystal quality of boron arsenide

• 作者: Zhenxing Liu Fangjie Deng Yuan Zhou Yanjie Liang Cong Peng Bing Peng Feiping Zhao Zhihui Yang Liyuan Chai
• 来源期刊: 矿物冶金与材料学报
• 年，卷（期）: 2022,（4）
• 页码范围: 662-670
• 页数: 9页
• 语种: 英文

摘要

Cubic boron arsenide (BAs) has attracted great attention due to its high thermal conductivity, however, its controllable, stable, and ideal preparation remains challenging. Herein, we investigated the effect of iodine-containing transport agents I2 and boron triiodide (BI3) on BAs synthesized and grown through chemical vapor transport. Results show that similar to the commonly used I2, BI3 accelerates the synthesis and improves the mass fraction of BAs from ～12％ to over 90％ at 820℃and 1.5 MPa, a value beyond the promoting effect of only increasing temperature and pressure. Both agents enhance the quality of BAs crystals by reducing the full width at half maximum by up to 10％–20％. I2 agglomerates the grown crystals with twin defects (～50 nm wide), and BI3 improves the crystal anisotropy and element uniformity of BAs crystals with narrow twins (～15 nm wide) and increases the stoichiometry ratio (～0.990) to almost 1. Owing to the boron interstitials from the excessive boron supply, the spacing of layers in {111} increases to 0.286 nm in the presence of I2. Owing to its coordinated effect, BI3 only slightly influences the layer spacing at 0.275 nm, which is close to the theoretical value of 0.276 nm. In the chemical vapor transport, the aniso-tropic crystals with flat surfaces exhibit single-crystal characteristics under the action of BI3. Different from that of I2, the coordinated effect of BI3 can promote the efficient preparation of high-quality BAs crystal seeds and facilitate the advanced application of BAs.