Huang Shenyang, Wang Fanjie, Zhang Guowei, Song Chaoyu, Lei Yuchen, Xing Qiaoxia, Wang Chong, Zhang Yujun, Zhang Jiasheng, Xie Yuangang, Mu Lei, Cong Chunxiao, Huang Mingyuan, Yan Hugen
State Key Laboratory of Surface Physics, Key Laboratory of Micro- and Nano-Photonic Structures (Ministry of Education), and Department of Physics, Fudan University, Shanghai 200433, China.
Institute of Flexible Electronics, Northwestern Polytechnical University, Xi'an 710072, China.
Phys Rev Lett. 2020 Oct 9;125(15):156802. doi: 10.1103/PhysRevLett.125.156802.
The temperature dependence of the band gap is crucial to a semiconductor. Bulk black phosphorus is known to exhibit an anomalous behavior. Through optical spectroscopy, here we show that the temperature effect on black phosphorus band gap gradually evolves with decreasing layer number, eventually turns into a normal one in the monolayer limit, rendering a crossover from the anomalous to the normal. Meanwhile, the temperature-induced shift in optical resonance also differs with different transition indices for the same thickness sample. A comprehensive analysis reveals that the temperature-tunable interlayer coupling is responsible for the observed diverse scenario. Our study provides a key to the apprehension of the anomalous temperature behavior in certain layered semiconductors.
带隙的温度依赖性对于半导体至关重要。已知体相黑磷表现出反常行为。通过光谱学，我们在此表明，温度对黑磷带隙的影响随着层数的减少而逐渐演变，最终在单层极限情况下转变为正常行为，实现了从反常到正常的转变。同时，对于相同厚度的样品，温度引起的光学共振位移也因不同的跃迁指数而有所不同。综合分析表明，温度可调的层间耦合是观察到的多种情况的原因。我们的研究为理解某些层状半导体中的反常温度行为提供了关键。
