Jean Massies

Lateral localization effects in strained InGaAs/GaAs semiconductor quantum wells grown on vicinal surfaces

We have studied different strained InGaAs/GaAs ultrathin quantum wells grown on vicinal surfaces for various terrace lengths and In contents. From photoluminescence experiments we observe an enhancement of the continuum density of states of quantum wells wit large In content (x equals 0.35). We associate this behavior to the localization of carriers in regions of quasi one-dimensional confinement which are induced by fluctuations in the lateral periodicity of the strained layers. This assumption is supported by time resolved measurements and explained through theoretical calculations.

Selective area sublimation of GaN for top-down fabrication of nanostructures (Conference Presentation)

A fraction of a SiNx mono-layer is formed on a GaN layer by exposing the surface to a Si flux. When the sample is heated under vacuum at high temperature (900°C), we observe the sublimation of GaN in the regions uncovered by the thermally resistant SiNx mask. This selective area sublimation (SAS) process can be used for the formation of nanopyramids and nanowires with a diameter down to 4 nm. Also, if InGaN quantum wells are included in the structures before sublimation, InGaN quantum disks with quasi identical sizes in the 3 dimensions of space can be formed using SAS.