Ultraviolet Random Lasing Action from Highly Disordered n-AlN/p-GaN Heterojunction

Abstract

Room-temperature random lasing is achieved from an n-AlN/p-GaN heterojunction. The highly disordered n-AlN layer, which was deposited on p-GaN:Mg layer via radio frequency magnetron sputtering, acts as a scattering medium to sustain coherent optical feedback. The p-GaN:Mg layer grown on sapphire provides optical amplification to the scattered light propagating along the heterojunction. Hence, lasing peaks of line width less than 0.4 nm are emerged from the emission spectra at round 370 nm for the heterojunction under forward bias larger than 5.1 V. Lasing characteristics of the heterojunction are in agreement with the behavior of random lasers.

Electrically pumped ultraviolet random lasing action from p-NiO/n-GaN heterojunction

“…This is because the NiO layer works like a grating layer of the DFB laser. This is similar to that in Yang's report [14].…”

“…The light within the heterojunction would be trapped and propagated inside the GaN layer via total internal reflection. This is because the differences of the refractive indices of sapphire, NiO, and GaN, which are approximately equal to 1.79, 2.33, and 2.64, respectively at ∼370 nm [18], forms an optical waveguide to confine light within the GaN layer [14]. Moreover, the light inside the NiO layer, experienced distributed multiple optical scattering, has the possibility to form closed-loop paths for light within the region under external excitation.…”

“…Moreover, high-quality GaN materials have been widely used for industrial production, therefore, GaN is probably a good choice for the realization of random laser diodes. However, up to now the reports on electrically pumped lasing of GaN based random laser diodes are very scarce [14]. Since the presence of multiple optical scattering and light amplification could lead to the random lasing action in the highly disordered random systems [15].…”

Barrier inhomogeneities limited current and 1/f noise transport in GaN based nanoscale Schottky barrier diodes

“…Accordingly, GaN nanostructures have been functionalized in various nanoscale devices such as light emitting diodes (LEDs)78, p-n junctions910, photodetectors1112, field-effect transistors1314, lasers1516 and solar cells1718. To realize a nanoscale device based on GaN nanorods (NRs), a thorough understanding of the current transport across interface is required as models which are used for explaining electrical transport in epitaxial films are not fully applicable to nano-devices because of small dimensions1920.…”

“…GaN nanostructures are intensively investigated due to advantages like capabilities of incorporation of both n- and p-type dopants 1 2 , strain relaxation when grown on lattice mismatched substrates 3 4 , dislocation free structures 5 and enhanced light absorption 6 . Accordingly, GaN nanostructures have been functionalized in various nanoscale devices such as light emitting diodes (LEDs) 7 8 , p-n junctions 9 10 , photodetectors 11 12 , field-effect transistors 13 14 , lasers 15 16 and solar cells 17 18 . To realize a nanoscale device based on GaN nanorods (NRs), a thorough understanding of the current transport across interface is required as models which are used for explaining electrical transport in epitaxial films are not fully applicable to nano-devices because of small dimensions 19 20 .…”