Development of green, yellow, and amber light emitting diodes using InGaN multiple quantum well structures

Abstract

The authors present optical and electrical data for long wavelength (573–601nm) InGaN∕GaN multiple quantum well light emitting diodes (LEDs) grown by metal organic chemical vapor deposition. These results are achieved by optimizing the active layer growth temperature and the quantum well width. Also, the p-GaN is grown at low temperature to avoid the disintegration of the InGaN quantum wells with high InN content. A redshift is observed for both the green and yellow LEDs upon decreasing the injection current at low current regime. In the case of the yellow LED, this shift is enough to push emission into the amber (601nm).

Built-in field control in alloyedc-plane III-N quantum dots and wells

“…Particularly, the amount of In that can be incorporated into InGaN and AlInN alloys while maintaining high crystal quality is currently for layered structures about 30% in both cases. 4,[57][58][59][60][61] In the case of QDs, higher In contents of up to $ 35% have been reported in InGaN QDs, 62,63 whereas AlInN QDs have not been studied significantly in the literature. Regarding strain, devices with as much as $ 1.1% compressive in-plane strain in the barriers along the whole active layer have been reported.…”

“…GaN/AlInN heterostructures Figure 3 shows the built-in field for a GaN QW (QD) embedded in an AlN (a) or InN (b) matrix, calculated using Eqs. (1) and (4). It can be seen that the resultant built-in field is of opposite sign in the GaN/InN structure compared to the GaN/AlN case, leading to the idea that an ad hoc superposition of the curves shown in Figs.…”

“…2,3 However, technical challenges still remain present, including for example the growth of high-quality In-rich InGaN systems, which would allow the implementation of efficient solutions for green, yellow and amber light emitting diodes (LED) and lasers (E g $ 2:0-2.5 eV). [3][4][5] UV radiation sources (E g > 3:4 eV) 1 are of interest for various applications such as optical storage, medical diagnostics and treatment, and sterilization processes. 6,7 In this spectral range, nitride-based structures might be either a good candidate for the replacement of traditional low-efficiency devices, or the only available solution in environments where it is not possible to implement any alternative approach.…”

Spectroscopic investigation of coupling among asymmetric InGaN/GaN multiple quantum wells grown on non-polar a-plane GaN substrates

“…First, a 750 nm layer of intrinsic GaN was deposited, followed by a 2.5 lm n-type layer of GaN:Si deposited at 975 C. Next, the reactor was switched to a 1-column flow mode for the MQWs using sources of triethylgallium (TEGa) and trimethylindium (TMIn) whose ratios were established with mass flow controllers as described previously. 15 Four In x Ga 1Àx N/GaN QWs (labeled 1-4) were fabricated at 620/650 C with a higher flow of NH 3 that doubled the V-III ratio. Subsequent energy dispersive x-ray spectroscopy indicated the In composition of the QWs varied from x ¼ 0.10-0.12.…”

“…The non-polar a-plane (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) GaN substrate was obtained by vertically slicing a low dislocation density (5Â10 5 -2Â10 6 cm À2 ) GaN boule grown along the polar c-plane (0001) direction. The MQW structure was grown on this substrate in a vertical flow metal-organic chemical vapor deposition (MOCVD) reactor designed to operate in two modes: a 2-column flow mode ( Fig.…”