Different influences of u-InGaN upper waveguide on the performance of GaN-based blue and green laser diodes

Abstract

Performances of blue and green laser diodes (LDs) with different u-InGaN upper waveguides (UWGs) are investigated theoretically by using LASTIP. It is found that the slope efficiency (SE) of blue LD decreases due to great optical loss when the indium content of u-InGaN UWG is more than 0.02, although its leakage current decreases obviously. Meanwhile the SE of the green LD increases when the indium content of u-InGaN UWG is varied from 0 to 0.05, which is attributed to the reduction of leakage current and the small increase of optical loss. Therefore, a new blue LD structure with In 0.05 Ga 0.95 N lower waveguide (LWG) is designed to reduce the optical loss, and its slope efficiency is improved significantly.

Controlling GaN-Based Laser Diode Performance by Variation of the Al Content of an Inserted AlGaN Electron Blocking Layer

“…The band gap of GaN-based nitrides is continuously adjustable in the range of 0.7 eV to 6.2 eV [ 1 , 2 ], and this excellent physical property allows GaN-based LDs to have broad application prospects in many fields, such as high-density optical storage, full-color display, chemical sensors and portable projectors [ 3 , 4 , 5 , 6 ]. In addition, III–V nitride nanostructures have excellent electrical, energy band and structural properties.…”

Effect of metallurgical step-graded quantum barrier on the performance of InGaN-based laser diode

“…Majorly, these devices are restricted by the built-in polarization and carrier deficiency in the active region [10], high amount of electron seepage [11], reduced threshold current density [12], limited laser power [13], and lower internal quantum efficiency [14]. Several structural modifications have been instilled in the basic LD structure in order to surpass these major issues and improve the overall performance of these devices; for example, an Al z Ga (1−z) N-based electron blocking layer (EBL) to control electrons overflowing from the active region [15], an Al c In d Ga (1-c-d) N quaternary EBL [16], quantum barriers (QBs) [17,18], and a superlattice configuration in the active region surrounding layers (cladding layers and waveguide layers) [19,20].…”