Engineering Near-Infrared Light Emission in Mechanically Exfoliated InSe Platelets through Hydrostatic Pressure for Multicolor Microlasing

gamma-indium selenide (InSe) is a van der Waalssemiconductor and holds great potentials for low-energy-consump-tion electronic and optoelectronic devices. Herein, we investigatedthe hydrostatic pressure engineered near-infrared (NIR) lightemission of mechanically exfoliated gamma-InSe crystals using the diamondanvil cell (DAC) technique. A record-wide spectral tuning range of185 nm and a large linear pressure coefficient of 40 nm GPa-1wereachieved for spontaneous emissions, leading to ultrabroadbandmicrolasing spectrally ranging from 1022 to 911 nm. This highemission tunability can be attributed to the compression of the softintralayer In-Se bonds under high pressure, which suppressed theband gap shrinkage by increasing the interlayer interaction.Furthermore, two band gap crossovers of valence (direct-to-indirect)and conduction bands were resolved at approximately 4.0 and 7.0 GPa, respectively, resulting in pressure-sensitive emission lifetimeand intensity. Thesefindings pave the pathways for pressure-sensitive InSe-based NIR light sources, sensors and so on

Automated summary

This study investigates the light emission properties of γ-indium selenide crystals under high pressure and finds that it has a wide spectral tuning range and high tunability. This can be attributed to the compression of the intralayer bonds and the band gap crossover phenomenon of different bands under high pressure.