燕山大学杨国春团队报了独特的B-C结构驱动具有高双极迁移率的Al₂B₁₂C。相关研究成果于2024年12月4日发表在国际顶尖学术期刊《美国化学会杂志》。

开发具有高双极迁移率的材料对于推进多功能应用至关重要，但此类材料仍然稀缺。目前，立方砷化硼（BAs）是首屈一指的双极性材料，在室温下表现出～1600 cm² V^–1 s^–1的双极性迁移率。

该文中，研究人员说明了半导体Al₂B₁₂C具有非板条B–C框架，其中C原子通过准sp³杂化与四个扭曲的六边形反棱柱B12单元的顶点结合，预计具有双极载流子输运行为。其双极迁移率可达～2095 cm² V^-1s^-1。

空穴输运起源于C pz轨道，该轨道将Al原子的电子捕获在价带最大值处，沿C轴方向形成C–Al–C空穴通道，而电子输运源于B12单元中的π电子。对于Al₂B₁₂C，极性光学声子散射是限制迁移率的主要机制。

此外，它在可见光谱中显示出高吸收系数（105 cm^-1）。这些吸引人的特性使Al₂B₁₂C成为电子和光伏器件应用中，极具前景的环保半导体。

附：英文原文

Title: Al2B12C with High Ambipolar Mobility Driven by a Unique B–C Framework

Author: Shicong Ding, Sheng Wang, Yong Liu, Eva Zurek, Li Zhu, Guochun Yang

Issue&Volume: December 4, 2024

Abstract: The development of materials with high ambipolar mobility is pivotal for advancing multifunctional applications, yet such materials remain scarce. Presently, cubic boron arsenide (BAs) stands out as the premier ambipolar material, demonstrating an ambipolar mobility of ～1600 cm2 V–1 s–1 at room temperature [Science 2022, 377, 433 and Science 2022, 377, 437]. Herein, we illustrate that semiconducting Al2B12C, featuring a nonclathrate B–C framework in which a C atom bonds to the vertices of four distorted hexagonal antiprism B12 units via quasi-sp3 hybridization, is predicted to possess ambipolar carrier transport behavior. Its ambipolar mobility can reach up to ～2095 cm2 V–1 s–1. The hole transport originates from the C pz orbitals that trap the electrons of Al atoms at the valence band maximum, forming a C–Al–C hole channel along the c-axis direction, whereas electron transport stems from the π electrons in B12 units. For Al2B12C, polar optical phonon scattering serves as the primary mechanism limiting mobility. Additionally, it displays a high absorption coefficient (105 cm–1) in the visible spectrum. These appealing properties make Al2B12C a highly promising environmentally friendly semiconductor for applications in electronics and photovoltaic devices.

DOI: 10.1021/jacs.4c11164

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c11164