Changes in electrical characteristics associated with degradation of InGaN blue light-emitting diodes

Because of the high concentration of threading dislocations, the reverse current-voltage (I–V) characteristics for either homo- or heterojunctions made on GaN-based materials grown on sapphire often show a strong electric field dependence (called a soft breakdown characteristic), which can be described by a power law I=Vn, with n between 4 to 5. We find a significant increase of reverse currents associated with the early degradation of emission in InGaN blue single-quantum-well light-emitting diodes (LEDs) subjected to aging tests (injected current of 70 mA over a total time of about 300 h). The formation of dislocations might be due to the relaxation of strain in the thin InGaN active layer during the aging tests.

[1]  A. G. Chynoweth,et al.  Effect of Dislocations on Breakdown in Silicon p-n Junctions , 1958 .

[2]  Henryk Temkin,et al.  Origin of conductivity and low-frequency noise in reverse-biased GaN p-n junction , 1998 .

[3]  V. Narayanamurti,et al.  Direct observation of localized high current densities in GaN films , 1999 .

[4]  A. N. Kovalev,et al.  Aging of InGaN/AlGaN/GaN Light-Emitting Diodes , 1997 .

[5]  Satoshi Kurai,et al.  Direct Evidence that Dislocations are Non-Radiative Recombination Centers in GaN , 1998 .

[6]  John F. Muth,et al.  Dominance of tunneling current and band filling in InGaN/AlGaN double heterostructure blue light‐emitting diodes , 1996 .

[7]  James S. Speck,et al.  Electrical characterization of GaN p-n junctions with and without threading dislocations , 1998 .

[8]  Shuji Nakamura,et al.  The Blue Laser Diode: GaN based Light Emitters and Lasers , 1997 .

[9]  M. Lampert,et al.  Current injection in solids , 1970 .

[10]  Joe C. Campbell,et al.  Comprehensive characterization of metal–semiconductor–metal ultraviolet photodetectors fabricated on single-crystal GaN , 1998 .

[11]  Takashi Jimbo,et al.  Characteristics of InGaN/AlGaN light-emitting diodes on sapphire substrates , 1997 .

[12]  M. Osiński,et al.  Tunneling current and electroluminescence in InGaN: Zn,Si/AlGaN/GaN blue light emitting diodes , 1997 .

[13]  Shuji Nakamura,et al.  High‐power InGaN single‐quantum‐well‐structure blue and violet light‐emitting diodes , 1995 .

[14]  Ishwara B. Bhat,et al.  Electrical characteristics of magnesium-doped gallium nitride junction diodes , 1998 .