HVPE-Grown AlN-GaN Based Structures for UV Spectral Region

In this paper we describe ultraviolet light emitting diodes (LEDs) emitting in the spectral range from 305 to 340 nm based on AlGaN/AlGaN multi-layer submicron heterostructures grown by hydride vapor phase epitaxy (HVPE). The developed HVPE process possesses unique features such as ability (i) to combine deposition of thick low-defect layers and thin device multi-layer structures in the same growth run and (ii) to easily grow high-quality AlGaN layers in the whole composition range. HVPE is carbon-free growth technique producing GaN materials with very low background impurity concentrations. For a packaged LED with the peak wavelength of 340 nm, an optical output power of 2 mW was achieved at pulsed injection currents of 110 mA. The obtained results prove the developed HVPE technique to have a significant potential for production of device epitaxial wafers, particularly for fabrication AlGaN-based light emitters.