Outcome：

2024
The mechanisms of passivation by metal oxide capping has been investigated. It has been suggested that organometallic precursors change the state of the oxide at the surface upon reaction.

2023
By comparing passivation capping by ZnO and AlOx, it was found that the crytallinity of the formed film and the self-cleaning process of the precursors play an important role in determining the properties of the surface quantum dots.

2022
By passivating surface InAs quantum dots, enhanced PL intensity with reduced wavelength peak was obtained.

MBE growth of InGaAs quantum structures using submonolayer (SML) stacking is studied thereby precisely controlling the structure and electronic properties of the quantum structures.
Further, the potential of applying such structures to spintronics is investigated.

Outcome：

2024
Studies on the dependence of parameters such as As pressure, growth interrupt, or InAs deposition, on the formation of nanostructures formed by submonolayer (SML) stack growth.

2023
Control of spin was shown by illuminating these 2D and 3D structures by circular polarized excitation light.

2022
The transition of 2D-3D in submonolayer growth has been studied and the critical conditions were identified and the mechanisms were studied.

Outcome：

2024
Modified preparation of quantum discs by SML stacking and measurement of their optical properties.

2023
Shown that quantum discs can be prepared by using SML stacking.

2022
Preparation of quantum discs that are considered to be a strong candidate for photon upconversion is being investigated.

Outcome：

2023
By comparing different precursor materials, the basic guidelines for passivating InAs surface quantum dots were proposed.

2022
The recipes and the mechanisms of passivating InAs surface quantum dots were studied.

Outcome：

2024
2D and 3D quantum structures have been grown usingU controlled SML stack growth, and their electronic properties have been studied by spin-polarized PL.
Basic studies on the mechanisms of SML stack growth has also been investigated.

2023
Controlled growth of 2D and 3D quantum structures by SML stack growth has been successfully demonstrated, and its device applications are under investigation.

2022
The transition of 2D-3D in submonolayer (SML) stack growth has been studied and the critical conditions were identified and the mechanisms were studied.

Outcome：

2023
Strain-free passivation capping of surface quantum dots by ALD metal oxide thin films was successfully demonstrated, and its device applications are under investigation.

2022
Atomic layer deposition (ALD) of metal oxide thin films are being investigated.

An attempt to realize short wavelength emission from oxide thin films.

Outcome：

2024
Exploration of methods for improving the films.

2023
Organizing the lab/equipment for improving the films.

2022
Short wavelength light emission from oxide films indicated.

To purpose is to investigate the deterministic fabrication of single-photon sources based on epitaxial quantum dots.

Submonolayer (SML) deposition by MBE is a method that was proposed to assembled InAs nanostructure while maintaining 2D (layer-by-layer) growth. However, it has recently been shown that under certain growth conditions, a transition from 2D to 3D growth regime occurs during SML growth. This process is interesting for both fundamental physics and potential applications.

Outcome：

2024
Further study of the 2D-3D transition during InAs/GaAs submonolayer deposition has been carried out. We have recently demonstrated fine control of the 3D QD density down to low densities of less than 1QD per square micron, which is beneficial for quantum information applications. Some of our latest results have been presented at the SPIE PW 2025 conference.

2023
We were able to investigate various factors that affect the 2D to 3D transition during SML growth. Some of the results have been presented in the JSAP Autumn Meeting 2023.