Scientific Reports (Sep 2021)

Dimension- and position-controlled growth of GaN microstructure arrays on graphene films for flexible device applications

  • Dongha Yoo,
  • Keundong Lee,
  • Youngbin Tchoe,
  • Puspendu Guha,
  • Asad Ali,
  • Rajendra K. Saroj,
  • Seokje Lee,
  • A. B. M. Hamidul Islam,
  • Miyoung Kim,
  • Gyu-Chul Yi

DOI
https://doi.org/10.1038/s41598-021-97048-2
Journal volume & issue
Vol. 11, no. 1
pp. 1 – 7

Abstract

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Abstract This paper describes the fabrication process and characteristics of dimension- and position-controlled gallium nitride (GaN) microstructure arrays grown on graphene films and their quantum structures for use in flexible light-emitting device applications. The characteristics of dimension- and position-controlled growth, which is crucial to fabricate high-performance electronic and optoelectronic devices, were investigated using scanning and transmission electron microscopes and power-dependent photoluminescence spectroscopy measurements. Among the GaN microstructures, GaN microrods exhibited excellent photoluminescence characteristics including room-temperature stimulated emission, which is especially useful for optoelectronic device applications. As one of the device applications of the position-controlled GaN microrod arrays, we fabricated light-emitting diodes (LEDs) by heteroepitaxially growing InxGa1−xN/GaN multiple quantum wells (MQWs) and a p-type GaN layer on the surfaces of GaN microrods and by depositing Ti/Au and Ni/Au metal layers to prepare n-type and p-type ohmic contacts, respectively. Furthermore, the GaN microrod LED arrays were transferred onto Cu foil by using the chemical lift-off method. Even after being transferred onto the flexible Cu foil substrate, the microrod LEDs exhibited strong emission of visible blue light. The proposed method to enable the dimension- and position-controlled growth of GaN microstructures on graphene films can likely be used to fabricate other high-quality flexible inorganic semiconductor devices such as micro-LED displays with an ultrahigh resolution.