High quality Quantum Dots for 1.55 micron wavelength on GaAs substrate

Extensions of emission wavelength of InAs/GaAs QDs by using bi-layer QD growth have been investigated.The extension has been found with an enlargement of the upper layer(Active)QDs occurred by optimizing several growth parameters：growth temperature of lower(Seed)QDs，amount of InAs supplied for seed-and active-QDs。These optimized parameters lowered the density of the seed-QDs strain spreading upward，which resulted in an enlargement of the active-QDs。We achieved a control of the extension of emission wavelength up to approximately 1.4·m.We also studied the growth of GaNAs/AlGaAs heterostructures on GaAs(100)substrates by plasma-assisted molecular beam epitaxy.By introducing periodic growth interruption and nitrogen(N)supply to the interrupted surfaces during the growth of GaNAs，we achieved high controllability of the average N concentration in GaNAs layers.We observed three-dimensional island growth of GaNAs on the N-rich surfaces.Extensions of emission wavelength of InAs/GaAs QDs by using bi-layer QD growth have been investigated.The extension has been found with an enlargement of the upper layer(Active)QDs occurred by optimizing several growth parameters：growth temperature of lower(Seed)QDs，amount of InAs supplied for seed-and active-QDs。These optimized parameters lowered the density of the seed-QDs strain spreading upward，which resulted in an enlargement of the active-QDs。We achieved a control of the extension of emission wavelength up to approximately 1.4·m.We also studied the growth of GaNAs/AlGaAs heterostructures on GaAs(100)substrates by plasma-assisted molecular beam epitaxy.By introducing periodic growth interruption and nitrogen(N)supply to the interrupted surfaces during the growth of GaNAs，we achieved high controllability of the average N concentration in GaNAs layers.We observed three-dimensional island growth of GaNAs on the N-rich surfaces.

Extensions of emission wavelength of InAs/GaAs QDs by using bi-layer QD growth have been investigated. The extension has been found with an enlargement of the upper layer (active) QDs occurred by optimizing several growth parameters: growth temperature of lower (seed) QDs, amount of InAs supplied for seed- and active-QDs. These optimized parameters lowered the density of the seed-QDs strain spreading upward, which resulted in an enlargement of the active-QDs. We achieved a control of the extension of emission wavelength up to approximately 1.4 ・m. We also studied the growth of GaNAs/AlGaAs heterostructures on GaAs (100) substrates by plasma-assisted molecular beam epitaxy. By introducing periodic growth interruption and nitrogen (N) supply to the interrupted surfaces during the growth of GaNAs, we achieved high controllability of the average N concentration in GaNAs layers. We observed three-dimensional island growth of GaNAs on the N-rich surfaces.Extensions of emission wavelength of InAs/GaAs QDs by using bi-layer QD growth have been investigated. The extension has been found with an enlargement of the upper layer (active) QDs occurred by optimizing several growth parameters: growth temperature of lower (seed) QDs, amount of InAs supplied for seed- and active-QDs. These optimized parameters lowered the density of the seed-QDs strain spreading upward, which resulted in an enlargement of the active-QDs. We achieved a control of the extension of emission wavelength up to approximately 1.4 ・m. We also studied the growth of GaNAs/AlGaAs heterostructures on GaAs (100) substrates by plasma-assisted molecular beam epitaxy. By introducing periodic growth interruption and nitrogen (N) supply to the interrupted surfaces during the growth of GaNAs, we achieved high controllability of the average N concentration in GaNAs layers. We observed three-dimensional island growth of GaNAs on the N-rich surfaces.