Low-temperature study of current and electroluminescence in InGaN/AlGaN/GaN double-heterostructure blue light-emitting diodes

Abstract

Electrical and optical properties of Nichia double-heterostructure blue light-emitting diodes, with In 0.06 Ga 0.94 N:Zn, Si active layer, are investigated over a wide temperature range from 10 to 300 K. Current-voltage characteristics have complex character and suggest the involvement of various tunneling mechanisms. At small voltages ͑and currents͒, the peak wavelength of the optical emission shifts with the applied bias across a large spectral range from 539 nm ͑2.3 eV͒ up to 443 nm ͑2.8 eV͒. Light emission takes place even at the lowest temperatures, indicating that a complete carrier freeze-out does not occur.

High-quality p–n junctions with quaternary AlInGaN/InGaN quantum wells

“…Much higher values of ideality factors Ϸ6-7 have been reported for GaN based p -n diodes and AlGaN/InGaN LEDs. [6][7][8] Such values are commonly attributed to the carrier tunneling rather than to the thermal diffusion and recombination. 6,7 In commercially available blue LEDs at low bias, the carrier tunneling in space charge region occurs either because of high doping of the active layer or due to the high density of localized states.…”

“…[6][7][8] For our structure, the temperature dependence of the I -V slopes is proportional to 1/kT with practically no temperature dependence of the ideality factor, . The fact that in our samples is close to 2 indicates that the recombination current is a major mechanism of the current transport, in contrast to commonly observed tunneling mechanism for standard blue AlGaN/ InGaN LEDs and GaN p -n diodes.…”

Effect of long-term aging on series resistance and junction conductivity of high-power InGaN light-emitting diodes

“…(The absolute errors for the values of the series resistance and energy parameter are determined by the method of least-squares used for the fitting of the experimental data to linear dependences.) The estimated values of the characteristic energy imply the values of the ideality factor are well above 2, which indicate the domination of injection due to tunnelling [17,18]. Differently from the series resistance, the above approach is seen to reveal no change in the energy parameter within the accuracy of the experiment.…”

“…The observed variation of the I-V characteristics was analysed within a generalized Shockley equation with exponential contributions of diffusion, recombination, and tunnel injection mechanisms peculiar to InGaN LEDs [17][18][19]:…”

High-frequency modeling of GaN∕SiC blue light-emitting diodes

“…12 Two different arguments have been defended to explain ideality factors above 2 in these devices, the existence of multiple junctions inside the device 12 and the presence of deep-level-assisted tunneling effects. [13][14][15] wave frequencies, and a no linear fit to the measured capacitance for the full range of frequencies. This fit was achieved with the following model:…”