Structural and Electronic Response of Multigap N-Doped In 2 Se 3 : A Prototypical Material for Broad Spectral Optical Devices.

The production of controlled doping in two-dimensional semiconductor materials is a challenging issue when introducing these systems into current and future technology. In some compounds, the coexistence of distinct crystallographic phases for a fixed composition introduces an additional degree of complexity for synthesis, chemical stability, and potential applications. In this work, we demonstrate that a multiphase In 2 Se 3 layered semiconductor system, synthesized with three distinct structures─rhombohedral α and β-In 2 Se 3 and trigonal δ-In 2 Se 3 ─exhibits chemical stability and well-behaved n-type doping. Scanning tunneling spectroscopy measurements reveal variations in the local electronic density of states among the In 2 Se 3 structures, resulting in a compound system with electronic bandgaps that range from infrared to visible light. These characteristics make the layered In 2 Se 3 system a promising candidate for multigap or broad spectral optical devices, such as detectors and solar cells. The ability to tune the electronic properties of In 2 Se 3 through structural phase manipulation makes it ideal for integration into flexible electronics and the development of heterostructures with other materials.