Carrier dynamics and lasing behavior of InAs/GaAs quantum dot lasers with short cavity lengths. (29th October 2021)

• Record Type: Journal Article
• Authors: Yao, Z H; Wang, X; Chen, H M; Wang, T; Qin, L; Liu, J; Zhang, Z Y
• Is Part Of: Nanotechnology. Volume 33:Number 3(2022)
• Publication Date: 2021-10-29
• Subjects: quantum dots -- modulation p-doping -- carrier dynamics -- facet coating -- short cavity; Nanotechnology -- Periodicals; Nanotechnology -- Periodicals; Nanotechnology; Publications périodiques; Nanotechnologies; Periodicals; 620.5
• DOI: 10.1088/1361-6528/ac2f5e
• Languages: English
• ISSNs: 0957-4484

Abstract

Abstract: The modulation p-doping technique has emerged as an effective way to optimize the carrier dynamics process of quantum dot (QD) structures. Here, the laser structures based on the 1.3 μ m multiple-layer InAs/GaAs QD were fabricated with and without modulation p-doping. The carrier relaxation rate was increased after modulation p-doping, as demonstrated by transient absorption spectroscopy. The higher relaxation rate in p-doped QDs could be explained by more rapid carrier–carrier scattering process originating from increasing of the hole quasi-Fermi-level movement that increases the probability of occupancy of the valence states. In addition, the lasing behavior of Fabry–Perot lasers with and without modulation p-doping was investigated and compared. It was found that the ground state (GS) lasing in the absence of facet coating was successfully achieved in a p-doped laser diode with short cavity length (400 μ m), which can be attributed to the higher GS saturation gain caused by p-doping. With assistance of a designed TiO2 /SiO2 facet coating whose central wavelength (∼1480 nm) is far beyond the lasing wavelength of 1310 nm, the GS lasing could be realized in a laser diode with short cavity lengths (300 μ m) under continuous wave operation at room temperature, implying great potential for the development of low-cost and high-speed directly modulated lasers.