B掺杂对金刚石热导率的影响  

Effect of B Doping on Thermal Conductivity of Diamond

作　　者：赵永生[1,2] 阎峰云 刘雪[3] ZHAO Yongsheng;YAN Fengyun;LIU Xue(State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology,Lanzhou 730050,China;School of Mechatronics Engineering,Lanzhou Institute of Technology,Lanzhou 730050,China;School of Petrochemical Engineering,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,兰州730050 [2]兰州工业学院机电工程学院,兰州730050 [3]兰州理工大学石油化工学院,兰州730050

出　　处：《材料导报》2024年第20期47-54,共8页Materials Reports

基　　金：甘肃省教育厅产业支撑计划项目(2021CYZC-34);甘肃省高等学校创新基金(2021B-310)。

摘　　要：金属基金刚石复合材料因其高导热率和低热膨胀系数而备受关注,掺B被广泛应用于改性金刚石表面。因此,有必要深入探究B掺杂对金刚石导热特性的影响。通过第一性原理计算,系统研究了金刚石掺杂B后的多项关键性质,包括电子特性、晶格振动、热力学性能、晶格热导率、声子群速度、声子自由程和声子寿命等。结果显示,当B掺杂浓度为12.5%(如无特别说明,均为原子分数)时,金刚石的热传输特性发生显著改变,最大晶格热导率降至452 W·m^(-1)·K^(-1)。其主要原因是引入B原子后,形成的C-B化合键为弱极性,导致金刚石的晶格振动不协调,晶格振动的简并现象消失,这意味着金刚石晶体的动力学稳定性被破坏。同时,掺杂B导致金刚石内部声子自由程由10^(4)nm降低为10^(2)nm,声子寿命由80 ps缩短为6 ps。本研究揭示了掺杂B原子对金刚石导热特性的影响机制,可为材料设计和应用提供有益的理论指导。Metal matrix diamond composites have gained significant attention due to their high thermal conductivity and low coefficient of thermal expansion.Boron doping is widely applied to modify the surface of diamonds.Therefore,it is necessary to investigate in-depth the impact of boron doping on the thermal conductivity properties of diamond.In this study,we conducted a systematic examination of various key properties of B-doped diamond using first-principles calculations.These properties encompass electronic characteristics,lattice vibrations,thermodynamic behavior,lattice thermal conductivity,phonon velocities,phonon mean free paths,and phonon lifetimes.(Our findings shed light on the intricate relationship between B doping and thermal behavior of diamond).Our results reveal that when the B doping concentration reaches 12.5at%,thermal transport characteristics of diamond undergo significant alterations,leading to a substantial decrease in the maximum lattice thermal conductivity to 452 W·m^(-1)·K^(-1).This change can be primarily attributed to the introduction of weakly polar C-B bonds by B atoms,disrupting lattice vibrations and eliminating lattice vibration degeneracy.As a consequence,these alterations affect lattice vibration properties and dynamic stability,ultimately impacting thermal transport.Furthermore,B doping has a noticeable impact on phonon behavior.Internal phonon mean free paths are reduced from 10^(4)nm to 10^(2)nm,resulting in diminished phonon propagation distances.Phonon lifetimes also experience a prominent reduction from 80 ps to as low as 6 ps due to the perturbation of lattice vibrations.This study provides in-depth insights into the mechanisms underlying the impact of B atom doping on thermal conductivity of diamond.The findings can offer valuable theoretical guidance for material design and applications(By elucidating these aspects,this research contributes to advancing the understanding of diamond materials and refining their utilization in various fields).

关 键 词：金刚石 B掺杂 热导率 第一性原理 

分 类 号：TB131[理学—物理]