讲座题目：纯相及碲掺杂黑磷单晶的生长

主讲人：严清峰副教授（清华大学）

讲座时间：2019年11月18日10:30

讲座地点：化工楼A316

讲座内容简介：Few-layer phosphorene has shown a plethora of exciting properties and applications, which can be exfoliated from orthorhombic black phosphorus (BP) single crystals. Here, we report the synthesis of orthorhombic BP single crystals through chemical vapor transport (CVT) reaction based on the red phosphorus/tin/iodine (RP/Sn/I2) system. An unencapsulated field-effect transistor (FET) based on a 6 nm thick BP nanoflake exfoliated from the as-grown BP single crystal exhibited an impressive hole mobility (μp) of 1744 cm²V^-1s^-1and an admirable on/off current switching ratio (I_on/I_off) of ~104. These results proved the high quality of the BP crystals synthesized by the CVT reaction method. Furthermore, we revealed that the BP nucleation and growth proceeded from the crystalline monoclinic violet or Hittorf’s phosphorus, which was accurately confirmed via a series of structural and optical experimental identifications and supported by quantum chemical studies. We thus proposed a step-by-step phase-induced nucleation and growth mechanism for the growth of BP single crystals by using CVT reaction in RP/Sn/I2 system. Tellurium (Te)-doped BP bulk single crystals were also synthesized based on CVT method. Uniform Te doping up to 0.5% atomic ratio was realized. We demonstrated the application of few-layer phosphorene in directing the self-assembly of asymmetric polystyrene-block-polymethylmethacrylate (PS-b-PMMA) block copolymer thin film and made a systematic cytotoxicity study of layered BP for potential biomedical applications.

主讲人简介：

严清峰，清华大学化学系长聘副教授，博士生导师，1993-2000年就读于武汉理工大学材料学院，获学士和硕士学位。2003年7月于中国科学院半导体研究所获博士学位。博士毕业后相继在新加坡国立大学、新加坡南洋理工大学、美国麻省理工学院开展博士后研究。2008年9月加入清华大学化学系，入选清华大学骨干人才计划，2010年获教育部“霍英东教育基金会青年教师基金”奖。担任中国材料研究学会青年工作委员会第六、七、八届理事。目前研究方向为人工功能晶体材料与材料化学，主持国家自然科学基金重大研究计划培育项目、国家自然科学基金面上项目、国家自然科学基金青年基金、韩国Samsung公司“全球研究拓展项目计划（GRO）”等项目，已发表SCI收录论文150余篇，其中第一作者和通讯作者论文90余篇。SCI总引用超过2500次，h因子25。