Tuning the band gap in InSb (100) by surface chemical doping

Surface chemical doping is known to induce an interface dipole electric field, which has recently attracted considerable attention for its capacity to modulate the electronic and optical properties of semiconducting materials. InSb is considered one of the most promising semiconducting crystals due to its exceptional electron and hole mobility, surpassing that of other common III-V semiconductors. Here, we demonstrated the tuning of band gap renormalization in InSb (100) through in situ surface potassium atom doping, directly observed using time- and angle-resolved photoelectron spectroscopy. In addition, density functional theory calculations were performed to analyze the band gap evolution in InSb under the electric field perpendicular to the (100) crystal plane. Our study not only provides a clear observation of the band gap renormalization of InSb but also highlights its potential to enhance practical applications in contemporary photoelectric devices based on InSb.