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Papers by Vinh Thành

Physical Review B, 2001

This work presents a study on the effect of a bimodal size distribution and of the pyramid/dome t... more This work presents a study on the effect of a bimodal size distribution and of the pyramid/dome transition to the optical properties of self-assembled Ge/Si quantum dots. The wetting layers are shown to be inhomogeneous in thickness due to lateral diffusion of Ge from two-dimensional ͑2D͒ layers towards islands of bimodal sizes, while the island-related photoluminescence remains unchanged. The results indicate that threedimensional islands, at their early stages of nucleation, are formed by consuming Ge from 2D layers and that the island luminescence energies are more sensitive to Ge/Si interdiffusion than the confinement effect inside the islands as currently believed.

Physical Review B, 2011

We investigate the chemical and morphological structure of the Au nanodots on Ge(111) which serve... more We investigate the chemical and morphological structure of the Au nanodots on Ge(111) which serve as catalysts for the formation of epitaxial Ge nanowires. The spatial localization of Au is investigated by X-ray spectromicroscopy and transmission electron microscopy. We show that dewetting of an Au film on Ge(111) gives rise to a thin Au-Ge wetting layer and Au-Ge dots. These dots are crystallized but not with a single crystallographic orientation. Thanks to the spatially resolved X-ray and transmission electron microscopy measurements, a chemical characterization of both binary Au-Ge catalysts and wetting layer is obtained at the nanoscale. We show that Ge vertical growth is achieved even without external Ge supply.

physica status solidi (b), 2001

We have investigated the midinfrared photoconductivity of Ge/Si self-assembled quantum dots. The ... more We have investigated the midinfrared photoconductivity of Ge/Si self-assembled quantum dots. The self-assembled quantum dots were grown by ultra-high-vacuum chemical vapor deposition on Si͑001͒. The photoresponse of the p-type device exhibits resonances in the midinfrared around 10 m wavelength. The resonance of the photocurrent shifts to lower energy as the applied bias increases. The photocurrent is weakly dependent on the incoming polarization of the infrared light. The photocurrent is analyzed in terms of bound-to-bound and bound-to-continuum transitions in the valence band. The photocurrent peaks are correlated to the photoluminescence of the device.

SCIENTIFIC JOURNAL OF TAN TRAO UNIVERSITY, 2020

Nghiên cứu nhằm đánh giá ảnh hưởng của việc sử dụng than sinh học thay thế một phần phân khoáng đ... more Nghiên cứu nhằm đánh giá ảnh hưởng của việc sử dụng than sinh học thay thế một phần phân khoáng đến sinh trưởng và năng suất ngô tại Việt Trì, Phú Thọ. Thí nghiệm thực hiện trên giống ngô VS36. Các công thức thí nghiệm được bố trí theo kiểu khối ngẫu nhiên hoàn chỉnh với 3 lần nhắc lại. Theo dõi các chỉ tiêu về sinh trưởng, năng suất và đánh giá hiệu quả sản xuất ngô. Kết quả thí nghiệm chỉ ra rằng khi sử dụng than sinh học thay thế cho 20% lượng phân khoáng, cây ngô vẫn có khả năng sinh trưởng phát triển tốt và cho năng suất đạt 42,68 tạ/ha tương đương với công thức đối chứng.