Enhancement of quantum well intermixing on InP/InGaAs/InGaAsP heterostructures using titanium oxide surface stressors to induce forced point defect diffusion

Quantum well intermixing was studied on InPInGaAsInGaAsP heterostructures under stress induced by a Ti Ox surface stressor. Results provide a comparison of thermal emission wavelength shift and effective emission wavelength shift for samples intermixed with and without applied stress. It is shown that Ti Ox decreases the measured thermal shift depending on the amplitude of the induced stress. It is also shown that the diffusion of point defects created during ion implantation prior to Ti Ox stressor deposition is significantly enhanced. This results in an increase of the effective wavelength shift by up to 300%. © 2006 American Institute of Physics.A. François, V. Aimez, J. Beauvais, M. Gendry and P. Regren

Band gap tuning of InAs∕InP quantum sticks using low-energy ion-implantation-induced intermixing

International audienc

Isolation of III-V/Ge Multijunction Solar Cells by Wet Etching

Microfabrication cycles of III-V multijunction solar cells include several technological steps and end with a wafer dicing step to separate individual cells. This step introduces damage at lateral facets of the junctions that act as charge trapping centers, potentially causing performance and reliability issues, which become even more important with today’s trend of cell size reduction. In this paper we propose a process of wet etching of microtrenches that allows electrical isolation of individual solar cells with no damage to the sidewalls. Etching with bromine-methanol, the solution that is typically used for nonselective etching of III-V compounds, results in the formation of unwanted holes on the semiconductor surfaces. We investigate the origin of holes formation and discuss methods to overcome this effect. We present an implementation of the isolation step into a solar cell fabrication process flow. This improved fabrication process opens the way for improved die strength, yield, and reliability

Measurement of strong photon recycling in ultra-thin GaAs n/p junctions monolithically integrated in high-photovoltage vertical epitaxial heterostructure architectures with conversion efficiencies exceeding 60%

International audienc

Technological developments of epitaxial lift-off process over InP substrates

International audienc

SEM characterization of nanodevices and nanomaterials

The scanning electron microscope (SEM) can be used to study and characterize a wide variety of materials used in nanoelectronic and photonic applications. Several different techniques make use of this versatile tool. These include voltage contrast in secondary electron imaging, charge collection for semiconductor samples and cathodoluminescence. These techniques are important in device nanofabrication process development and nanomaterials characterization. © 2006 IEEE

Measured output voltages of ~24V from photovoltaic devices designed with the vertical epitaxial heterostructure architecture (VEHSA) grown monolithically with 20 ultra-thin p/n junctions by MOCVD

International audienc

Towards miniaturization of concentrated photovoltaics (CPV): impacts on fabrication, performance and robustness of solar cells

International audienc