InPBi Quantum Dots for Super-Luminescence Diodes

Novel InGaSb/AlP Quantum Dots for Non-Volatile Memories

Non-volatile memories based on the flash architecture with self-assembled III-V quantum dots (SAQDs) used as a floating gate are one of the prospective directions for universal memories. The central goal of this field is the search for a novel SAQD with hole localization energy (E_loc) sufficient for a long charge storage (10 years). In the present work, the hole states' energy spectrum in novel InGaSb/AlP SAQDs was analyzed theoretically with a focus on its possible application in non-volatile memories. Material intermixing and formation of strained SAQDs from a Ga_xAl_1-xSb_yP_1-y, In_xAl_1-xSb_yP_1-y or an In_xGa_1-xSb_yP_1-y alloy were taken into account. Critical sizes of SAQDs, with respect to the introduction of misfit dislocation as a function of alloy composition, were estimated using the force-balancing model. A variation in SAQDs' composition together with dot sizes allowed us to find that the optimal configuration for the non-volatile memory application is GaSbP/AlP SAQDs with the 0.55-0.65 Sb fraction and a height of 4-4.5 nm, providing the E_loc value of 1.35-1.50 eV. Additionally, the hole energy spectra in unstrained InSb/AlP and GaSb/AlP SAQDs were calculated. E_loc values up to 1.65-1.70 eV were predicted, and that makes unstrained InGaSb/AlP SAQDs a prospective object for the non-volatile memory application.

GaAs-Based InPBi Quantum Dots for High Efficiency Super-Luminescence Diodes

InPBi exhibits broad and strong photoluminescence at room temperature, and is a potential candidate for fabricating super-luminescence diodes applied in optical coherence tomography. In this paper, the strained InPBi quantum dot (QD) embedded in the AlGaAs barrier on a GaAs platform is proposed to enhance the light emission efficiency and further broaden the photoluminescence spectrum. The finite element method is used to calculate the strain distribution, band alignment and confined levels of InPBi QDs. The carrier recombinations between the ground states and the deep levels are systematically investigated. A high Bi content and a flat QD shape are found preferable for fabricating super-luminescence diodes with high efficiency and a broad emission spectrum.