InGaN/GaN multilayer quantum dots yellow-green light-emitting diode with optimized GaN barriers

Abstract

InGaN/GaN multilayer quantum dot (QD) structure is a potential type of active regions for yellow-green light-emitting diodes (LEDs). The surface morphologies and crystalline quality of GaN barriers are critical to the uniformity of InGaN QD layers. While GaN barriers were grown in multi-QD layers, we used improved growth parameters by increasing the growth temperature and switching the carrier gas from N2 to H2 in the metal organic vapor phase epitaxy. As a result, a 10-layer InGaN/GaN QD LED is demonstrated successfully. The transmission electron microscopy image shows the uniform multilayer InGaN QDs clearly. As the injection current increases from 5 to 50 mA, the electroluminescence peak wavelength shifts from 574 to 537 nm.

Strong localization effect and carrier relaxation dynamics in self-assembled InGaN quantum dots emitting in the green

“…In the last 2 decades, growth techniques of InGaN QDs, i.e., metalorganic chemical vapor deposition (MOCVD) and molecular-beam epitaxy (MBE), are extensively studied and well developed. By using these methods, InGaN QD LEDs and LDs, which emit from green to red, have recently been demonstrated with superior performance over equivalent QW-based counterparts [ 13 - 17 ]. However, only few optical investigations on the carrier transport and relaxation in InGaN QDs have been made to further understand the carrier recombination processes [ 18 - 20 ].…”

Surface morphology and optical properties of InGaN quantum dots with varying growth interruption time

“…Oliver et al reported the realization of micro-disk InGaN laser on sapphire substrates via growth interruption method [21]. Other research groups also employ the similar growth interruption methods to improve the optical properties of light emitting devices [22][23][24][25]. In this work, we investigated the effect of different growth interruption time on the surface morphology and optical properties of InGaN QDs grown on 2-inch silicon substrates.…”

Effect of small flow hydrogen treatment at the upper well/barrier interface on the properties of InGaN/GaN multiple quantum wells

“…Elevating the growth temperature of GaN quantum barrier (QB) is found to be an effective way to improve the quality of active region [13]. Although the growth temperature of QB is usually 50-150 higher than that of QW, it is still [14,15], growth interruption [16,17] and indium treatment [18][19][20]. Recently, Ren et al demonstrated that full hydrogen treatment after GaN barrier layer growth can enhance both indium incorporation and quantum efficiency [21].…”