Zeolite framework silicon allotropes with direct band gap

It is a significant issue in the field of semiconductor devices and optoelectronic devices to find silicon allotropes with high mobility, direct band gap and high light absorption to replace traditional diamond silicon (d-Si). By constructing a zeolite framework, fifteen silicon allotropes with a direct band gap of 0.47–1.66 eV were screened from hundreds of zeolite framework silicon allotropes by ab initio calculations. The crystal structures, stability, effective mass, mechanical, electronic and optical properties were comprehensively studied. Compared with diamond silicon, several allotropes showed easy doping, low carrier effective mass and high absorption of the solar spectrum, which indicate promising candidates for adoption in photovoltaic applications.