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 

机构地区：[1]School of Metallurgy and Environment,Central South University,Changsha 410083,China [2]Chinese National Engineering Research Center for Control&Treatment of Heavy Metal Pollution,Changsha 410083,China

出　　处：《International Journal of Minerals,Metallurgy and Materials》2022年第4期662-670,共9页矿物冶金与材料学报（英文版）

基　　金：financially supported by the National Key R&D Program of China(Nos.2018YFC1900302 and 2020YFC1909201);the National Science Fund for Distinguished Young Scholars(No.51825403)。

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 I_(2) and boron triiodide(BI_(3))on BAs synthesized and grown through chemical vapor transport.Results show that similar to the commonly used I_(2),BI_(3) 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%.I_(2) agglomerates the grown crystals with twin defects(~50 nm wide),and BI_(3) 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 I_(2).Owing to its coordinated effect,BI_(3) 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 anisotropic crystals with flat surfaces exhibit single-crystal characteristics under the action of BI_(3).Different from that of I_(2),the coordinated effect of BI_(3) can promote the efficient preparation of high-quality BAs crystal seeds and facilitate the advanced application of BAs.

关 键 词：boron arsenide transport agent boron-arsenic reaction IODINE boron triiodide 

分 类 号：TQ128.1[化学工程—无机化工]