Unraveling the Infrared Detection Properties of Bi2Te3 Depending on Thickness from Semiconductor to Metal Surface States

Abstract

Bi2Te3 emerges as a promising candidate material for the next generation of mid-wave to long-wave Infrared photodetection due to its exceptionally narrow bandgap (approximately 0.2 eV). Furthermore, its topological insulator structure is safeguarded by time-reversal symmetry, leading to electronic structures that differentiate between surface and bulk states, exhibiting distinctive optoelectronic properties. Here, this study examines the infrared detection mechanism of Bi2Te3 across various thickness aims aimed to elucidate the transport behavior and characteristics of internal carriers in Bi2Te3 under the complex interplay between the bulk state and surface states The thickness of the Bi2Te3 film was controlled by adjusting the number of pulses in the pulsed laser deposition process, and the bandgap demonstrates a dependency on thickness. The photoelectric response mechanism of Bi2Te3 at different layer thicknesses was investigated, and the charge carrier transport dynamics across layers were clarified. In a word, it offers a theoretical basis for advancing photoelectric detection devices designed to regulate Bi2Te3 at distinct thicknesses.