摘要
针对K2CsSb光电阴极生长过程中可能存在的K3Sb、K2CsSb和Cs3Sb三种化合物,采用基于密度泛函理论的第一性原理计算方法,分别建立这三种锑化物阴极材料的立方结构体模型和(111)表面模型,获得了其电子结构与光学性质.对于体模型,计算得到了能带结构、态密度和光学性质,而对于表面模型,计算得到了功函数、光学性质和表面能.结果表明,三种锑化物阴极在中微子与闪烁体作用辐射能量范围(2.4~3.2eV)内,K2CsSb体材料的吸收系数和反射率与Cs3Sb、K3Sb体材料相近,而K2CsSb(111)表面的吸收系数和反射率低于其他两种阴极的(111)表面.此外,K3Sb的禁带宽度最小、功函数最大且表面能最大,Cs3Sb的表面能最小,其功函数与K2CsSb相近但禁带宽度比K2CsSb小,而K2CsSb禁带宽度最大,功函数和表面能都较小,因此K2CsSb阴极在蓝紫光波段适合作为一种稳定高效的光电发射材料.
Considering the possible existence of three types of compounds,namely K3Sb,K2CsSb and Cs3Sb in the growth of K2CsSb photocathode,a first-principles study based on density functional theory was employed to establish the cubic bulk models and the(111)surface models for the three types of antimonide cathode materials.Through theoretical calculations,electronic structures and optical properties were obtained,wherein band structures,densities of states and optical properties were acquired for bulk models,and work function,optical properties and surface energy were calculated for(111)surface models.The results demonstrate that,as for the three types of antimonide cathodes,in the radiation energy range of 2.4~3.2 eV produced by interaction between neutrinos and scintillators,the absorption and relectivity of K2CsSb bulk material are close to those of Cs3Sb and K3Sb ones,whereas the values of K2CsSb(111)surface material are lower than those of Cs3Sb and K3Sb ones.In addition,K3Sb has the narrowest bandgap,maximum work function and maximum surface energy,while Cs3Sb has the minimum surface energy and its work function is close to that of K2CsSb,but its band gap is smaller than that of K2CsSb.By contrast,K2CsSb with the widest bandgap has the smaller work function and surface energy.Therefore,K2CsSb photocathode is suitable to serve as a stable and high-efficient photoemitter in the blue-violet spectral region.
作者
康天佑
任玲
张锴珉
金睦淳
王兴超
舒昭鑫
张益军
钱芸生
KANG Tian-you;REN Ling;ZHANG Kai-min;JIN Mu-chun;WANG Xing-chao;SHU Zhao-xin;ZHANG Yi-jun;QIAN Yun-sheng(School of Electronic and Optical Engineering,Nanjing University of Science and Technology,Nanjing 210094,China;North Night Vision Technology Co.,Ltd,Nanjing 211106,China)
出处
《光子学报》
EI
CAS
CSCD
北大核心
2020年第1期197-204,共8页
Acta Photonica Sinica
基金
国家重大科学仪器设备开发专项（No.2016YFF0100400）
国家自然科学基金（No.61771245)~~
关键词
锑化物阴极
第一性原理
电子结构
光学性质
Antimonide cathodes
First-principles
Electronic structures
Optical properties
