Output light power of InGaN-based violet laser diodes improved by using a u-InGaN/GaN/AlGaN multiple upper waveguide

Abstract

The upper waveguide (UWG) has direct influences on the optical and electrical characteristics of the violet laser diode (LD) by changing the optical field distribution or barrier of the electron blocking layer (EBL). In this study, a series of InGaN-based violet LDs with different UWGs are investigated systematically with LASTIP software. It is found that the output light power (OLP) under an injecting current of 120 mA or the threshold current (I th ) is deteriorated when the UWG is u-In 0.02 Ga 0.98 N/GaN or u-In 0.02 Ga 0.98 N/Al x Ga 1−x N (0 ≤ x ≤ 0.1), which should be attributed to small optical confinement factor (OCF) or severe electron leakage. Therefore, a new violet LD structure with u-In 0.02 Ga 0.98 N /GaN/Al 0.05 Ga 0.95 N multiple layer UWG is proposed to reduce the optical loss and increase the barrier of EBL. Finally, the output light power under an injecting current of 120 mA is improved to 176.4 mW.

Enhancing performance of GaN-based LDs by using GaN/InGaN asymmetric lower waveguide layers

“…[11,12], and slightly lower than that in Ref. [13]. The dependence of threshold current and output power (under an injection current of 160 mA) on InGaN insertion thickness as shown in Fig.…”

“…There remain some problems to be solved further in the realization of high power GaN LD, such as high total optical loss and optical field leakage. Many methods have been proposed to suppress the total optical loss and improve the optical field distribution for GaN-based violet LDs, such as complex upper waveguide, [11][12][13] undoped thickoptical-waveguide (TOW) layer, [14,15] and the nanoporous GaN cladding layers. [16] These complex structures with undoped InGaN wave guides are difficult to realize the high qual-ity epitaxy on a quantum well structure, especially near a p-AlGaN electron barrier layer with high doping concentration.…”

Influence mechanism of growth temperature and pressure on surface morphology and defects of InGaN materials

“…With a change in wavelength, the PL luminescence intensity of the GaN peak at room temperature firstly decreased and then increased. When the In content is low (<6%), the valence band order between InGaN and the surface GaN is lower (<3KT), and a part of the photogenerated minority carriers are thermally excited to the surface for recombination [20]. When the temperature was appropriately increased, the In content increased, and the carrier confinement effect was strengthened.…”

Effect of Substrate Surface on Deposition of AlGaN: A Molecular Dynamics Simulation

“…III-Nitrides have attracted much attention over the past decades due to their excellent optoelectronic and physical properties [1][2][3]. Benefitting from an adjustable band gap (3.4 eV to 6.2 eV), AlGaN alloys are widely used in the area of optical devices such as laser diodes (LDs) [4], light emitting diodes (LEDs) [5] and photodetectors [6]. Especially in deep ultraviolet LED (DUV-LEDs), AlGaN/AlN superlattices (SLs) are used for filtering dislocations and relieving stresses [7].…”