@article{Dai2023, 
author = {Xueting Dai and Feng Qin and Caiyu Qiu and Ling Zhou and Junwei Huang and Fanghua Cheng and Xiangyu Bi and Caorong Zhang and Zeya Li and Ming Tang and Shengqiang Wu and Xiaoxu Zhao and Yangfan Lu and Huiyang Gou and Hongtao Yuan},
title = {Selective substitution induced anomalous phonon stiffening within quasi-one-dimensional P–P chains in SiP2},
year = {2023},
journal = {Nano Research},
volume = {16},
number = {1},
pages = {1107-1114},
keywords = {photoluminescence, Raman, phosphide, SiP2, quasi-one-dimensional structure},
url = {https://www.sciopen.com/article/10.1007/s12274-022-4703-x},
doi = {10.1007/s12274-022-4703-x},
abstract = {Light-matter interactions in low-dimensional quantum-confined structures can dominate the optical properties of the materials and lead to optoelectronic applications. In anisotropic layered silicon diphosphide (SiP2) crystal, the embedded quasi-one-dimensional (1D) phosphorus–phosphorus (P–P) chains directly result in an unconventional quasi-1D excitonic state, and a special phonon mode vibrating along the P–P chains, establishing a unique 1D quantum-confined system. Alloying SiP2 with the homologous element serves as an effective way to study the properties of these excitons and phonons associated with the quasi-1D P–P chains, as well as the strong interaction between these quasiparticles. However, the experimental observation and the related optical spectral understanding of SiP2 with isoelectronic dopants remain elusive. Herein, with the photoluminescence and Raman spectroscopy measurements, we demonstrate the redshift of the confined excitonic peak and the stiffening of the phonon vibration mode  B1g3 of a series of Si(P1−xAsx)2 alloys with increasing arsenic (As) compositions. This anomalous stiffening of  B1g3 is attributed to the selective substitution of As atoms for P atoms within the P–P chains, which is confirmed via our scanning transmission electron microscopy investigation. Such optical spectra evolutions with selective substitution pave a new way to understand the 1D quantum confinement in semiconductors, offering opportunities to explore quasi-1D characteristics in SiP2 and the resulting photonic device application.}
}