Authorship：Lead author   Publishing type：Research paper (scientific journal)   Publisher：AIP  

Authorship：Lead author   Publishing type：Research paper (scientific journal)   Publisher：AIP  

Authorship：Last author   Publishing type：Research paper (scientific journal)   Publisher：JSAP  

Authorship：Lead author   Publishing type：Research paper (scientific journal)   Publisher：IOP  

Authorship：Lead author   Publishing type：Research paper (scientific journal)   Publisher：Wiley-VHC  

Authorship：Lead author   Publishing type：Research paper (scientific journal)   Publisher：AIP  

Authorship：Lead author   Publishing type：Research paper (scientific journal)   Publisher：Wiley-VHC  

Authorship：Lead author   Publishing type：Research paper (scientific journal)   Publisher：AIP  

Presentation type：Oral presentation (general)  

Presentation type：Oral presentation (general)  

MBEによるGaAs(001)上のInAs量子ドットの GaAs によるキャッピング中のAs流量等の影響に関する報告。

Presentation type：Oral presentation (general)  

Presentation type：Oral presentation (general)  

MBEによるサブモノレイヤー積層法を用いたInAs/GaAsの成長における積層変調を用いた量子ドット密度の制御に関する報告。

Presentation type：Oral presentation (general)  

ALD法によるDEZを用いたInAs量子ドットのパッシベーション被覆によるPL発光強度の増強に関する報告。

Presentation type：Oral presentation (general)  

MBE で InAs/GaAs 交互積層するサブモノレイヤー成長法を用いて量子構造を作製する際の、GaAs 層の膜厚による構造制御の結果を報告した。

Presentation type：Oral presentation (general)  

Presentation type：Oral presentation (general)  

Photoluminescence enhancement of InAs surface quantum dots by Al2O3 passivation using atomic layer deposition was reported.

Presentation type：Oral presentation (general)  

Presentation type：Oral presentation (general)  

GaAs(001)上にMBEで成長されるInAs量子ドットについて、GaAsで被覆する際の初期過程で相互拡散や歪による形状変化と電子物性を検討した結果を報告した。

Presentation type：Oral presentation (general)  

The influence of underlying quantum dots (QDs) on InAs surface quantum dots (SQDs) on their photoluminescence (PL) properties were discussed. The insertion of underlying QDs resulted in enhancement of the PL intensity, and the wavelength was shown to be controlled by the spacer layer thickness.

Presentation type：Oral presentation (general)  

Presentation type：Oral presentation (general)  

Presentation type：Oral presentation (general)  

Stacked submonolayer (SML) growth of InAs nanostructures by MBE has been gaining interest recently for various optoelectronic applications. In contrast to the well-known Stranski-Krastanov (SK) growth of InAs nanostructures, stacked SML growth involves the cycled deposition of SML-thick InAs and few ML-thick GaAs. We have recently reported evidence of the 2D to 3D transition in SML InAs nanostructures. This transition leads to the existence of two distinct kinds of stacked SML nanostructures: 2D islands and 3D structures. Compared to the analogous transition in SK growth, the properties of the stacked SML transition is not yet well investigated. Hence, this study aims to elucidate the controllability of the density of 3D structures by As2 flux. It will be demonstrated that a wide control of 3D structure density (10^8 ~ 10^10 cm^-2) is possible simply by adjusting the As2 flux in stacked SML growth.

Presentation type：Oral presentation (general)  

The correlation between the structural and photo-luminescence (PL) properties of InAs submonolayer (SML) nanostructures at the 2D to 3D transition is in-vestigated. Significant changes in the topography of uncapped InAs nanostructures assembled by SML growth have been observed, indicating the transition from 2D to 3D growth regime. The influence of these structural changes to the luminescence properties of the nanostructure are investigated by PL measure-ments.

Presentation type：Oral presentation (invited, special)  

Presentation type：Oral presentation (general)  

The submonolayer (SML) growth mode has been attracting attention as an alternative to the well-known Stranski-Krastanov (SK) growth mode as a method of assembling InAs nanostructures, e.g. quantum dots (QDs), on GaAs by MBE. While the 2D to 3D transition in SK-growth has been well investigated with a critical thickness of ~1.7 ML, different conditions are employed for SML-growth. Here, atomic force microscopy (AFM) is utilized to study the topographical changes at the 2D to 3D transition in InAs SML nanostructures.

Presentation type：Oral presentation (general)  

Deemed

Presentation type：Oral presentation (general)  

GaAs(001)上に、SML法とSK法でIn(Ga)As量子ドットを作製し、成長条件の適正化により、幅広い波長範囲を持った近赤外蛍光体の実現を目指している経過を報告。

Presentation type：Oral presentation (general)  

Presentation type：Oral presentation (general)  

Below-bandgap states induced by pre-epitaxial growth treatments in GaAs have been investigated by photoluminescence (PL). Various electronic states giving rise to near-infrared (NIR) PL peaks are generated through processes such as annealing or buffer growth that are standard for epitaxial growth of InAlGaAs structures on (001) GaAs substrates. These states often overlap with those from InGaAs structures, not only complicating the interpretation by also altering the electronic properties of the devices. The present work provides guides for distinguishing the desired electronic states from the pregrowth treatment-induced defect states.

Presentation type：Oral presentation (general)  

Below-bandgap photoluminescence (PL) from GaAs has been investigated. We find that various electronic states giving rise to near-infrared (NIR) PL peaks can be generated through processes that are standard for epitaxial growth of InAlGaAs structures on (001) GaAs substrates. The PL signals from these states overlap with those from InAs quantum dots, wetting layers, and InGaAs structures, complicating the design of devices for telecommunications or intermediate band solar cells. The present result provides guides for distinguishing the desired electronic states from the thermal treatment-induced defect states.

Presentation type：Oral presentation (general)  

We report the observation of below-GaAs-bandgap photoluminescence (PL) emission from GaAs substrates subjected to thermal annealing during the standard pre-MBE-growth processes. Using below-bandgap excitation as well as backside PL measurements, defects deep within the substrates were probed. A broad PL emission peak at 1000 nm appear after pre-bake annealing at 300° and further defects at 905 and 1150 nm appear after oxide desorption annealing at 600°. These findings confirm the presence of optically-active defects in pre-MBE-growth annealed GaAs substrates.