Manipulation of Stark Broadening and Carrier Multiplication in Photoexcited InSb

Stark broadening and carrier multiplication are critical nonequilibrium-state phenomena in optoelectronic materials. However, the current absence of effective control methodologies significantly limits the practical applications of these materials. Here we investigate the electronic band structure and carrier dynamics in photoexcited indium antimonide (InSb) by a combination of time- and angle-resolved photoelectron spectroscopy with the in situ evaporation of cesium atoms. By precisely engineering the interfaces to generate dipole electric fields, the Stark broadening effect on the valence band is monotonically diminishing in strength. Simultaneously, we observed enhanced carrier multiplication in photoexcited InSb under the influence of surface doping. Through density function theory calculations incorporating the interface electric field, we not only reproduced the Stark broadening phenomenon but also provided direct evidence for the reduction in Fröhlich scattering strength. Our work demonstrates an ingenious approach to control Stark broadening and carrier multiplication in InSb, which holds great potential for improving the efficiency of energy devices such as photodetectors, solar cells, and light-emitting diodes.