Onset of surface stimulated emission at 260 nm from AlGaN multiple quantum wells

Abstract

We demonstrated onset of deep-ultraviolet (DUV) surface stimulated emission (SE) from c-plane AlGaN multiple-quantum well (MQW) heterostructures grown on a sapphire substrate by optical pumping at room temperature. The onset of SE became observable at a pumping power density of 630 kW/cm 2. Spectral deconvolution revealed superposition of a linearly amplified spontaneous emission peak at k $ 257.0 nm with a full width at half maximum (FWHM) of $12 nm and a superlinearly amplified SE peak at k $ 260 nm with a narrow FWHM of less than 2 nm. In particular, the wavelength of $260 nm is the shortest wavelength of surface SE from III-nitride MQW heterostructures to date. Atomic force microscopy and scanning transmission electron microscopy measurements were employed to investigate the material and structural quality of the AlGaN heterostructures, showing smooth surface and sharp layer interfaces. This study offers promising results for AlGaN heterostructures grown on sapphire substrates for the development of DUV vertical cavity surface emitting lasers (VCSELs). V

100‐nm thick single‐phase wurtzite BAlN films with boron contents over 10%

“…In spite of the development progress of edge‐emitting DUV lasers, development of DUV VCSELs has been lagging. Recently, the onset of surface stimulated emission at 260 nm from AlGaN multiple quantum wells (MQWs) by optical pumping has been reported . However, a true VCSEL requires distributed Bragg reflectors (DBRs) that are transparent and have reflectivity close to unity with sufficient bandwidth.…”

Demonstration of single-phase wurtzite BAlN with over 20% boron content by metalorganic chemical vapor deposition

“…Due to their unique properties such as lattice, optical, and polarization constants, they are promising for potential applications in UV devices, distributed Bragg reflectors (DBRs), power electronic devices, radiation tolerant electronics, and other optoelectronic components. [1][2][3][4][5][6][7][8][9] However, at present many epitaxial challenges need to be addressed to achieve high quality and to increase the boron content while maintaining the wurtzite phase, such as phase separation, limited thin film thickness, and limited adatom diffusion length. [10][11][12][13][14][15] The boron content of the wurtzite BAlN alloys has been limited to less than 15% with a relatively small thickness of 100 nm, which greatly limits the device applications of the BAlN alloys.…”

Induction-heating MOCVD reactor with significantly improved heating efficiency and reduced harmful magnetic coupling

“…In contrast, for Design B, as shown in Fig. 7(b), Although the proposed design (Design B) is aimed at the EHT MOCVD process, it is important to note that it can be employed at lower temperatures as well, such as below 1300 °C for the epitaxy of high-quality Al-rich AlGaN materials and structures [15,39]. This is because the advantages of Design B over Design A are still profound at lower temperatures because it enables the use of the close-distance showerhead for reduced premature reactions.…”