Multi‐Wavelength Laser Emission by Hot‐Carriers Transfers in Perovskite‐Graphene‐Chalcogenide Quantum Dots

Abstract As a new type of photonic‐chip light source, quantum dot (QD) lasers have recently received remarkable attention. However, two significant problems remain to be solved: the high lasing threshold characteristics and the single wavelength application in a photonic chip. To achieve this, a multi‐wavelength quantum dot laser is proposed. An ultrathin QDs‐film laser with a thickness of 78 nm is developed. The microstructure of MAPbBr 3 + graphene + CoGaZnS is studied using Raman spectroscopy and simulation, illustrating the different optical bandgap structures in different combinations. Four‐wavelength lasing at 540, 628, 769, and 824 nm with thresholds of 25 kW cm –2 and 50 kW cm –2 are achieved at room temperature. The finite‐difference time‐domain (FDTD) simulation results suggest a photon‐jumping phenomenon in a fixed period. Subsequently, the transient absorption (TA) spectrum of the QDs‐film is measured to reveal the ultrafast photonics process, which proves the two hot‐carrier transfer processes and the zitterbewegung (ZB) phenomenon in graphene at 416 nm. The ZB‐dominated hot‐carrier transfer from perovskite MAPbBr 3 to CoGaZnS is confirmed. This study can contribute to hot‐carrier lasing and light‐source research in photonic chips.