Strain-induced yellow to blue emission tailoring of axial InGaN/GaN quantum wells in GaN nanorods synthesized by nanoimprint lithography

Abstract

GaN nanorods (NRds) with axial InGaN/GaN MQWs insertions are synthesized by an original cost-effective and large-scale nanoimprint-lithography process from an InGaN/GaN MQWs layer grown on c-sapphire substrates. By design, such NRds exhibit a single emission due to the c-axis MQWs. A systematic study of the emission of the NRds by time-resolved luminescence (TR-PL) and power dependence PL shows a diameter-controlled luminescence without significant degradation of the recombination rate thanks to the diameter-controlled strain tuning and QSCE. A blueshift up to 0.26 eV from 2.28 to 2.54 eV (543 nm to 488 nm) is observed for 3.2 nm thick InGaN/GaN QWs with an In composition of 19% when the NRds radius is reduced from 650 to 80 nm. The results are consistent with a 1-D based strain relaxation model. By combining state of the art knowledge of c-axis growth and the strong strain relieving capability of NRds, this process enables multiple and independent single-color emission from a single uniform InGaN/GaN MQWs layer in a single patterning step, then solving color mixing issue in InGaN based nanorods LED devices.

Review on 3D Fabrication at Nanoscale

“…A large volume of studies exist in the literature that have explored NIL-based technology for creating 3D nanoscale structures (Fig. 9) using various promising materials [37][38][39][40][41]. The NIL process carries simplicity, low cost and high throughput.…”

“…(a) Large-area nanogap-controlled 3D nanoarchitectures (Reproduced with permission [37]. Copyright 2021, American Chemical Society); (b) GaN nanorods with axial InGaN/GaN quantum well insertions (Reproduced from[38]. CC BY 4.0.…”

Uncovering the carrier dynamics of AlInGaN semiconductors using time-resolved cathodoluminescence

“…For the case of Metzner et al [70] above, it is possible that this is not a factor due to the microstructural nature of the QWs investigated. Nanostructure-based III-nitrides have been reported to carry less residual strain than the bulk material [78][79][80]. Although the structures by Metzner et al [70] are not nanostructures, it is possible that their relatively small size could lead to strain relaxation.…”

“…[70] above, it is possible that this is not a factor due to the microstructural nature of the QWs investigated. Nanostructure-based III-nitrides have been reported to carry less residual strain than the bulk material [78-80]. Although the structures by Metzner et al.…”

Mapping of Fabry–Perot and whispering gallery modes in GaN microwires by nonlinear imaging

“…GaN is one of the most promising III-V semiconductor materials for applications in nonlinear photonics due to strong second and third order nonlinear optical properties, direct bandgap (3.4 eV) and compatibility with high operational temperatures (melting point is 2500 °C) [4,5]. The non-centrosymmetric crystal structure of GaN exhibits prominent piezo-electric properties suitable for applications in integrated electrooptical components and sensing devices [6,7].…”