Comparison of blue and green InGaN∕GaN multiple-quantum-well light-emitting diodes grown by metalorganic vapor phase epitaxy

Abstract

InGaN / GaN multiple-quantum-well ͑MQW͒ blue and green-light-emitting diodes ͑LEDs͒ were grown on sapphire substrates using metalorganic vapor phase epitaxy. High-resolution transmission microscopy shows that a much larger density of stacking faults exist in the quantum-well region of the blue LEDs than in the green LEDs. In the green LEDs, the blueshift in the electroluminescence ͑EL͒ emission energy at larger driving currents is more prominent than in the blue LEDs, which is explained by different strength of quantum-confined Stark effect as a result of different piezoelectric field intensity by different scales of strain relaxation in the blue and green MQWs. The steady broadening of the EL emission energy linewidth on the higher energy side with the increase of the driving current was observed in both blue and green LEDs, which is attributed to the band filling effect.

Carrier distribution in InGaN/GaN tricolor multiple quantum well light emitting diodes

“…Experimental information about carrier distributions can be obtained from quantum well structures with different indium content in each of the InGaN quantum wells: each well then emits its own characteristic color. [3][4][5][6][7] In this way one can also monitor how a carrier distribution evolves with increasing bias current. The factors that determine the carrier transport between quantum wells are the effective mass of the carriers, and the height and thickness of the barriers, both in the conduction band and in the valence band.…”

Improvement of optical and electrical properties of indium tin oxide layer of GaN-based light-emitting diode by surface plasmon in silver nanoparticles

“…The EL emission wavelength is slightly blue-shifted from 467 nm at 20 mA to 463 nm at 100 mA with the increased injection current. The EL peak shift towards the higher energy side with the increased injection current is caused by a screening effect of the polarizationinduced electric field by the carriers and also by the band-filling effect of the localized energy states formed by potential fluctuation in the MQWs [21]. Fig.…”

Enhanced light extraction in light-emitting diodes with photonic crystal structure selectively grown on p-GaN

“…The EL peak shift toward a higher energy side, with the increasing injection cur- rent, is due to a screening effect of the polarization-induced electric field by carriers and to the band-filling effect of the localized energy states formed by potential fluctuation in MQWs. 18 As shown in Fig. 4͑a͒, there are no peak shifts in the EL emission peaks of both LEDs at the same current.…”