High-power hybrid GaN-based green laser diodes with ITO cladding layer

Abstract

Green laser diodes (LDs) still perform worst among the visible and near-infrared spectrum range, which is called the “green gap.” Poor performance of green LDs is mainly related to the p-type AlGaN cladding layer, which on one hand imposes large thermal budget on InGaN quantum wells (QWs) during epitaxial growth, and on the other hand has poor electrical property especially when low growth temperature has to be used. We demonstrate in this work that a hybrid LD structure with an indium tin oxide (ITO) p-cladding layer can achieve threshold current density as low as 1.6 kA / cm 2 , which is only one third of that of the conventional LD structure. The improvement is attributed to two benefits that are enabled by the ITO cladding layer. One is the reduced thermal budget imposed on QWs by reducing p-AlGaN layer thickness, and the other is the increasing hole concentration since a low Al content p-AlGaN cladding layer can be used in hybrid LD structures. Moreover, the slope efficiency is increased by 25% and the operation voltage is reduced by 0.6 V for hybrid green LDs. As a result, a 400 mW high-power green LD has been obtained. These results indicate that a hybrid LD structure can pave the way toward high-performance green LDs.

Review of laser‐diode pumped Ti:sapphire laser

“…18,26 However, the challenges of fabricating longer wavelength GaN-based LDs are numerous and become more severe as the laser wavelength increases, which means that it is more difficult to manufacture high power GaN-based green LDs than blue LDs. 15,[27][28][29] The peak gain of GaNbased LDs decreases as the emission wavelength increases from violet to green range, which will result of the much lower efficiency of the green LDs than that of blue LDs. 30 Therefore, the output power of the green LDs has been relatively low for a long time.…”

Comparative spectroscopic investigation of Dy3+ ions in different sesquioxide solid solution ceramics

“…However, the complexity and high cost of those methods limit the application of yellow lasers. In comparison, the yellow laser system, obtained by directly pumping rare earth ions through solid‐state lasers, has a simple structure and high conversion efficiency 6,7 . The Dy 3+ ion has the potential for yellow laser generation, owing to the high intensity of 4 F 9/2 → 6 H 13/2 transition in the 4f–4f energy level transitions.…”

“…In comparison, the yellow laser system, obtained by directly pumping rare earth ions through solid-state lasers, has a simple structure and high conversion efficiency. 6,7 The Dy 3+ ion has the potential for yellow laser generation, owing to the high intensity of 4 F 9/2 → 6 H 13/2 transition in the 4f-4f energy level transitions. A yellow laser was first realized by directly pumping Dy-doped KY(WO 4 ) 2 and KGd(WO 4 ) 2 crystals through an Xe-flashlamp.…”

High Power Impulse Magnetron Sputtering of In2O3/Sn Cold Sprayed Composite Target

“…Although various new materials, such as tin dioxide (SnO 2 ) [ 10 ], zinc oxide (ZnO) [ 11 , 12 ], indium zinc oxide (IZO) [ 13 ], conductive nano-silver wire [ 14 ], have been applied in industry, ITO is still the main choice for conductive optical [ 15 ]. Its excellent photoelectric performance demonstrate potential in high efficiency optoelectronic devices including solar cells [ 16 ], touch screens [ 17 ], panel displays [ 17 ], organic light emitting diodes [ 18 ], electro-optic switches [ 19 ], liquid crystal devices (LCDs) [ 20 ], but also sensors for electronic skins [ 12 ] or thin film photovoltaics [ 21 ].…”