| New generations of projectors are based on laser diodes: red (based on (AlGaIn) (AsP)), green and blue (both based on (AlGaIn) N). Laser projectors have much better spatial and color resolution, and in future, they will provide three-dimensional images without the need of goggles. Three-dimensionality is realized by emitters of slightly different wavelengths, which allows for a slight spatial deviation of each of the laser beams. One of the unique technologies of making such matrices is lateral patterning proposed by the Institute of High Pressure Physics of the Polish Academy of Sciences, i.e., changes in the off-orientation of the growth surface from the direction of the crystallographic planes and small dimensions of the stripes. Thanks to that, we obtain spatially different incorporation of indium into InGaN quantum wells, emitting waves in the range of 380-550 nm. The technology of blue matrices (445-455 nm) has been implemented at TopGaN. The presented Project aims to develop the basics of matrix technology emitting in the green range (520-540 nm). Technologically, this range is more difficult than the blue one because the concentration of indium must be higher (over 25% compared to 15-20%). The growth temperature of quantum wells must be lower, which results in low surface mobility of atoms, poor surface morphology, incorporation of impurities and the formation of point defects. Therefore, green emitters have lower efficiencies than the blue one. The proposed project aims to develop the basics of epitaxy for green laser diode arrays on the patterned GaN substrates. Optimizations will include the growth parameters of the InGaN quantum wells and the p-layers in order to prevent decomposition of these wells while ensuring a high concentration of holes. The Project implementation should lead, within three years, to the implementation of the results at TopGaN and the launch of the production of green laser matrices on the GaN substrates laterally patterned. |
