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

Abstract

We report on quaternary AlInGaN/InGaN multiple quantum well (MQW) light emitting diode structures grown on sapphire substrates. The structures demonstrate high quality of the p–n junctions with quaternary MQW. At low forward bias (below 2 V), the temperature dependent of current–voltage characteristics are exponential with the ideality factor of 2.28, which is in a good agreement with the model of the injected carrier recombination in the space charge region. This ideality factor value is approximately three times lower than for conventional GaN/InGaN light emitting diodes (LEDs). The obtained data indicate the recombination in p–n junction space charge region to be responsible for a current transport in LED structures with quaternary quantum wells. This is in contrast to InGaN based LEDs, where carrier tunneling dominates either because of high doping of the active layer or due to the high density of localized states.

Effect of the AlGaN electron blocking layer thickness on the performance of AlGaN-based ultraviolet light-emitting diodes

“…The large value of ideality factor (42) implies that the tunneling mechanism dominates the carrier transport in the 310 nm LEDs rather than the diffusion or the space charge recombination process. The possible tunneling mechanisms include carriers that tunnel into as well as out of active region directly and/or via intermediate states present within the energy gap [9][10][11][12][13]. The latter mechanism is especially significant due to presence of the high density of impurities as well as dislocations in the nitride semiconductors, particularly the p-type layer [11,12].…”

Study of pinholes and nanotubes in AlInGaN films by cathodoluminescence and atomic force microscopy

“…This flexibility allows the lattice strain of heterostructures ͑e.g., InGaN quantum wells with AlInGaN barriers͒ to be varied between compressive, zero, and tensile strain. Enhanced crystal quality has been observed in quantum heterostructures of AlInGaN/InGaN, 11,12 and the piezoelectric field produced by the strain was eliminated 13 by using lattice matched AlInGaN/InGaN templates.…”

Diffusion and tunneling currents in GaN/InGaN multiple quantum well light-emitting diodes

“…Unrealistic ideality factors of 4-6 in these devices were observed. Recently, Chitinis et al [5] demonstrated a high-quality AlInGaN/InGaN multiple quantum well (MQW) LED structure by incorporation of a small amount of In into the AlGaN barrier layers. The electrical characteristics showed an ideality factor of 2.28, which was close to the theoretical prediction for carrier recombination in the space-charge region.…”