GaN-based blue laser diodes

Abstract

We report our recent progress on GaN-based high-power laser diodes (LDs), which will be applied as a light source in high-density optical storage systems. We have developed raised-pressure metal-organic chemical vapour deposition (RP-MOCVD), which can reduce the threading-dislocation density in the GaN layer to several times 108 cm-2, and demonstrated continuous-wave (cw) operation of GaN-based LD grown by RP-MOCVD. Furthermore, we found that the epitaxial lateral overgrowth (ELO) technique is useful for further reducing threading-dislocation density to 106 cm-2 and reducing the roughness of the cleaved facet. By using this growth technique and optimizing device parameters, the lifetime of LDs was improved to more than 1000 hours under 30 mW cw operation at 60 °C. Our results proved that reducing both threading-dislocation density and consumption power is a valid approach to realizing a practical GaN-based LD. On the other hand, the practical GaN-based LD was obtained when threading-dislocation density in ELO-GaN was only reduced to 106 cm-2, which is a relatively small reduction as compared with threading-dislocation density in GaAs- and InP-based LDs. We believe that the multiplication of non-radiative centres is very slow in GaN-based LDs, possibly due to the innate character of the GaN-based semiconductor itself.

Luminescence in Rare Earth Ion‐Doped Oxide Compounds

“…Research on tellurite glasses is currently being performed because several of its properties can be used in different types of modern devices [24][25][26]. These glasses show wide transmission in the 0.4-5.0-μm range, high linear and nonlinear refractive index, good corrosion resistance, thermal and chemical stability, and they are capable of incorporating large concentrations of rare earth ions into the matrix [27,28].…”

Fabrication and optical characterization of GaN waveguides on (−201)-oriented β-Ga_2O_3

“…Gallium Nitride (GaN), a wide-bandgap (band-gap energy of 3.4 eV for Wurtzite GaN) semiconductor with high electron velocity and chemical and thermal stability [1], has attracted immense research interests for its many commercial applications, such as solid-state lighting, high-power and high-frequency electronics, and blue semiconductor lasers [2][3][4][5]. Similar to other III-V semiconductor platforms [6][7][8], high-optical-quality GaN is also expected to become a suitable candidate for integrated nonlinear photonic circuits for a wide range of applications spanning from all-optical signal processing to quantum computing.…”

Development of 2" AlN Substrates Using SiC Seeds

“…• optoelectronic devices emitting light in the visible and UV spectral ranges (Orton & Foxon, 1998), including sources for general illumination (Craford, 2005;Liu, 2009;Miyajima et al, 2001;Nakamura et al, 2000;Schubert & Kim, 2005;Schubert, 2006;Taguchi, 2003;Zukauskas et al, 2002),…”