Recent results on the physical origin of the degradation of GaN-based LEDs and lasers

With this paper we describe recent results on the physical mechanisms responsible for the gradual degradation of GaN-based laser diodes and Light-Emitting Diodes (LEDs). The results described in the following were obtained by means of an extensive electrical and optical characterization of laser diodes and LEDs submitted to accelerated stress conditions. The experimental evidence described within this paper demonstrate that: (i) during stress, the threshold current of laser diodes can significantly increase, possibly due to a diffusion-related process; (ii) slope efficiency of laser diodes does not significantly change as a consequence of stress; (iii) LED samples - with the same epitaxial structure of laser diodes - show a significant decrease in optical power during stress time; degradation is more prominent at low measuring current levels, suggesting that it is due to the increase in non-radiative recombination; (iv) the worsening of the optical characteristics of LEDs and laser diodes is significantly correlated to the increase in the defect-related current components. Results described within this paper strongly support the hypothesis that the degradation of laser diodes and LEDs submitted to stress at high current densities (>4 kA/cm2) is due to the increase in the concentration of defects within the active layer of the devices, activated by the high flux of accelerated carriers through the quantum-well region.

[1]  G. Meneghesso,et al.  Extensive Analysis of the Degradation of Blu-Ray Laser Diodes , 2008, IEEE Electron Device Letters.

[2]  P. Wisniewski,et al.  InGaN Laser Diode Degradation. Surface and Bulk Processes , 2009 .

[3]  Masao Ikeda,et al.  High‐power pure blue laser diodes , 2007 .

[4]  Alfred Lell,et al.  Facet degradation of GaN heterostructure laser diodes , 2005 .

[5]  S. Nakamura,et al.  Room‐temperature continuous‐wave operation of InGaN multi‐quantum‐well structure laser diodes , 1996 .

[6]  Gaudenzio Meneghesso,et al.  Degradation of InGaN-based laser diodes analyzed by means of electrical and optical measurements , 2010 .

[7]  Andreas Breidenassel,et al.  500 nm electrically driven InGaN based laser diodes , 2009 .

[8]  P. Wisniewski,et al.  Degradation mechanisms in InGaN laser diodes grown on bulk GaN crystals , 2006 .

[9]  M. Meneghini,et al.  A Review on the Physical Mechanisms That Limit the Reliability of GaN-Based LEDs , 2010, IEEE Transactions on Electron Devices.

[10]  Dimitri Dini,et al.  Burn-in mechanism of 450 nm InGaN ridge laser test structures , 2009 .

[11]  S. Sze,et al.  Physics of Semiconductor Devices: Sze/Physics , 2006 .

[12]  S. Goto,et al.  Dislocation related issues in the degradation of GaN-based laser diodes , 2004, IEEE Journal of Selected Topics in Quantum Electronics.

[13]  Stewart Edward Hooper,et al.  Performance and degradation characteristics of blue–violet laser diodes grown by molecular beam epitaxy , 2009 .

[14]  Shigetaka Tomiya,et al.  Structural Defects and Degradation Phenomena in High-Power Pure-Blue InGaN-Based Laser Diodes , 2010, Proceedings of the IEEE.

[15]  Stewart Edward Hooper,et al.  Degradation of InGaN∕GaN laser diodes analyzed by microphotoluminescence and microelectroluminescence mappings , 2008 .

[16]  K. Streubel,et al.  Identification of aging mechanisms in the optical and electrical characteristics of light-emitting diodes , 2001 .

[17]  Piotr Perlin,et al.  InGaN Laser Diode Degradation , 2013 .