Photoluminescence in Analysis of Surface and Interfaces of Semiconductor Nanostructures

The intensity and excitation energy is chosen for different materials to probe different regions and excitations concentrations in the sample. The intensity of the PL signal provides information on the quality of surfaces and interfaces. Also, information on the electronic bands structure and the SC Energy gap can be obtained, as well as thermodynamics quantities such as temperature. For this experiment we just compared the photoluminescence (PL) spectra of AlGaAs/GaAs quantum wells (QWs) with different well widths (100 Å and 85 Å) and InAs/GaAs quantum dots (QD) structures as well as the theoretical aspects were covered. The sample are held in a cryostat and excited by a Helium-Neon laser. The emitted light is then captured by an optical fiber plugged to a spectrometer The optical fibre is plugged to a spectrometer equipped with a CCD detector, driven by a computer allowing us to acquire data. And this was used to avoid interaction between charge carriers and thermally excited phonons, it was used cryogenic temperature around 2k to cool the sample. simply with the theoretical models this experiement allows to collect numerous information about the lowest band to band transition in semiconductor materials.and for quantum dots which was the last sample in this study couldn’t be resolved individually.