Growth modification via indium surfactant for InGaN/GaN green LED

Abstract

In this work, indium (In) was introduced as a surfactant during growth of high temperature GaN quantum barriers (QBs) and GaN interlayer of InGaN/GaN green LEDs. A reference LED grown without In-surfactant was also included for comparison. Results suggested that the LED growth was improved by introducing the In-surfactant, especially during the growth of the GaN interlayer. The In-surfactant improved the morphology of the interlayer, hence allowed it to serve as a good surface growth for the LED. Moreover, the LED showed the lowest FWHM of each XRD satellite peak when the In-surfactant was introduced in the GaN interlayer, suggesting an effective way to improve the multi-quantum wells (MQWs). The introduction of the In-surfactant in the GaN interlayer and GaN QBs growths shifted the emission wavelength of the corresponding LEDs towards red (λemission = 534 nm) with respect to the reference LED where λemission = 526 nm. Furthermore, the In-surfactant introduction reduced the forward voltage, Vf of the corresponding LEDs down to 4.56 V, compared to the reference LED with Vf of 5.33 V. It also allowed the LEDs to show faster carrier decay lifetime, and hence higher radiative recombination, particularly when it was introduced in the GaN interlayer growth.

Recent Progress in Long‐Wavelength InGaN Light‐Emitting Diodes from the Perspective of Epitaxial Structure

“…In general, the indium content in InGaN quantum wells (QWs) is %22% or more for green or longer wavelength LEDs in comparison to 15%-17% for blue counterparts. [12] Unfortunately, InGaN LEDs suffer from a dramatic decrease in the quantum DOI: 10.1002/adpr.202300061 Over the last decades, continuous technological advancements have been made in III-nitride light-emitting diodes (LEDs), so that they are considered as a promising replacement of traditional light sources. With the emission wavelength covering the entire visible spectrum, InGaN LEDs find various applications such as solid-state lightings, full-color displays, and visible light communication.…”

“…[88] The and 590 nm via changing the InGaN QW thickness. [89] Bai et al demonstrated (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22) semipolar green to amber LEDs on overgrown GaN on microrod template, showing reduced blueshift compared to c-plane LEDs. [90] Christophe et al grew InGaN MQWs on m-plane nonpolar GaN at low temperature to enhance In incorporation and achieved light emission of 500-550 nm.…”

“…In general, the indium content in InGaN quantum wells (QWs) is ≈22% or more for green or longer wavelength LEDs in comparison to 15%–17% for blue counterparts. [ 12 ] Unfortunately, InGaN LEDs suffer from a dramatic decrease in the quantum efficiency with increasing indium composition in QWs for longer wavelength emission ( Figure ). This phenomenon is commonly known as “green gap.” The origin of “green gap” is still a matter of debate and two dominant origins have been proposed to explain this phenomenon [ 13 ] : crystal quality degradation and quantum‐confined Stark effect (QCSE).…”