Low threshold current density in GaInN-based laser diodes with GaN tunnel junctions

Abstract

We demonstrated room-temperature pulsed-operations of GaN-based blue edge-emitting laser diodes (LDs) with both the top and bottom AlInN cladding layers by using GaN tunnel junctions (TJs) grown by metalorganic vapor phase epitaxy. The LDs with a 1.2 mm cavity length and a 15 μm ridge width were fabricated. We obtained a low threshold current density of 0.9 kA cm−2 with facet coating. We found that while an optical absorption loss in the waveguiding layer was reduced with a low Mg concentration (3 × 1018 cm−3), that in a highly doped TJ could be an obstacle to obtain further improvements of the laser characteristics.

Globalization in Photonics Research and Development

“…KACST and KAUST have also invested heavily in semiconductor epitaxy growth equipment to fuel research based on molecular beam epitaxy (MBE) and metal-organic vapor phase epitaxy (MOVPE) [117] semiconductor growth technique. KACST-KAUST have collaborated on group-III nitride light-emitters on various heterogeneous substrates using MBE (led by TIC-SSL co-principal-investigator, Tien Khee Ng [https://cemse.kaust.edu.sa/photonics/people/person/tien-khee-ng]), especially in addressing the research gaps in the ultraviolet regime and the "green gap" [118]- [120].…”

“…The team realized InGaN-based red LED [122], [123] and optical communication based on the device [124]. Subsequently, the team demonstrated the first all-InGaN-based RGB micro-LEDs and at high pixel density, which is significant for immersive visual experiences requiring ultra-high brightness and definition [117]. It is also noted that Professor Ohkawa has demonstrated the first 740-nm InGaN-based red LEDs in 2012 [125].…”

Recent development of UV-B laser diodes

“…104) A sufficiently high optical confinement factor of 3.5% was achieved, which is comparable to that of typical GaInN-based laser diodes. 105) On the other hand, the p-type AlGaN cladding layer contains AlGaN with a lower AlN molar fraction than that of the active layer to form a ptype ohmic electrode, which may cause optical loss due to optical absorption. Assuming that the cladding layer has a lower bandgap energy than the active layer and acts as an absorber layer, the internal loss was estimated to be only a few cm −1 , indicating the formation of a favorable optical cavity.…”

Recent Progress in III‐Nitride Tunnel Junction Light‐Emitting Diodes

“…[20,21] The n-type layer acts as a transparent conductive nitride layer, facilitating efficient current spreading across the MQWs. [22][23][24][25] In this review, we first theoretically analyze the working principles of TJ and discuss several methods to improve tunneling probability, including increasing doping levels, polarization engineering, and introducing midgap states. Next, we summarize the mainstream techniques for fabricating TJ, such as metal-organic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE), and identify the key issues involved in these processes.…”

“…[ 20,21 ] The n‐type layer acts as a transparent conductive nitride layer, facilitating efficient current spreading across the MQWs. [ 22–25 ]…”