การศึกษาโครงสร้างควอนตัมเวลล์ของอินเดียมแกลเลียมอาร์เซไนด์/แกลเลียมอาร์เซไนด์ที่เตรียมโดยวิธีการปลูกผลึกด้วยลำโมเลกุล / ณัฐชัย สร้อยมาดี = A study on InGaAs/GaAs quantum well structure grown by molecular beam epitaxy / Nutchai Sroymadee
An experimental study has been performed on the quantum well structures of InGaAs/GaAs grown by Molecular Beam Epitaxy technique (MBE). The investigations were conducted to study the following effects, i.e. substrate temperature used in the growth process, well width of the quantum well, atomic ratio between In and Ga and finally As partial flux pressure. Photoluminescense (PL) technique was an effective tool to characterize all quantum well samples with different growth parameters. The results gathered from the PL peaks reveal the optimum growth temperature ranging from 500 to 530 ํC. In addition, good quantum structures should be grown at the lowest allowed temperature. PL peaks of quantum samples with different well widths have their positions varying with the well widths. Strain occurring inside the quantum well has been confirmed by the narrow PL peak. Different atomic ratios were experimented by two comparable means, i.e. partial flux control and opened-shutter time control. The later method is very useful to precisely control atomic ratio of InGaAs layer. This experiment divulges the PL peak positions varying with the atomic ratios. The variation of As partial flux pressure eventually confirms that the As pressure value of 20 time over Ga partial flux pressure is the optimum condition to grow the best crystal quality. All experimental data are useful to approximate the wavelength of the photon, ranging from 870 nm to 1000 nm at room temperature, emitted from different designed quantum well structures.
