Development of AlGaN nanostructures for electron-pumped UV lasers
Published : 15 July 2019
III-nitrides (GaN, AlN, InN and their ternary alloys) are wide-bandgap semiconductors, particularly attractive for opto- and microelectronics. This material family has experienced an extraordinary worldwide development, giving rise to a new generation of light emitting devices, laser diodes, photodetectors, and power-electronics components. The “Nanophysics and Semiconductors” laboratory at CEA-Grenoble is an internationally recognized R&D center in the field of III-nitride semiconductors. This laboratory is involved in a number of national and international projects with the target to apply III-N nanostructures for the development of innovative devices.
There is a strong demand for deep-UV lasers for applications such as Lidar remote detection, non-line-of sight communication, chem-bio sensing, 3D printing, etc. This spectral range is currently covered by gas lasers or lasers based on frequency conversion, which are bulky, inefficient, and inflexible in wavelength. AlGaN-based laser diodes should provide an alternative solution, but their implementation is held back by difficulties to fabricate highly-conductive p-AlGaN cladding layers.
The target of this PhD project is to develop a new compact UV-laser technology based on the excitation of AlGaN nanostructures by an electron beam from a carbon nanotube cathode. We target Peltier-cooled quasi-continuous-wave devices at 350 nm and 265 nm, with an output power > 500 mW. The choice of wavelengths aims at a direct comparison with the Nd-YAG technology. However, the operation principle of UVLASE allows selecting the emission wavelength by design, without degradation of the efficiency in the 350-250 nm range.
The student will join the research team working on III-nitride nanostructures. Device structures will be designed and synthesized in the laboratory, and the student will participate in their structural and optical characterization. He/she will be trained will be trained in the use of molecular-beam epitaxy, photoluminescence, cathodoluminescence and modeling of the electronic structure using the Nextnano commercial software. He/she will participate in the device fabrication in the PTA cleanroom facilities (http://pta-grenoble.com/).