title: Self-planarized quantum-disks-in-nanowires ultraviolet-B emitters utilizing pendeo-epitaxy.
abstract: The growth of self-assembled, vertically oriented and uniform nanowires (NWs) has remained a challenge for efficient light-emitting devices. Here, we demonstrate dislocation-free AlGaN NWs with spontaneous coalescence, which are grown by plasma-assisted molecular beam epitaxy on an n-type doped silicon (100) substrate. A high density of NWs (filling factor >95%) was achieved under optimized growth conditions, enabling device fabrication without planarization using ultraviolet (UV)-absorbing polymer materials. UV-B (280-320 nm) light-emitting diodes (LEDs), which emit at ∼303 nm with a narrow full width at half maximum (FWHM) (∼20 nm) of the emission spectrum, are demonstrated using a large active region ("active region/NW length-ratio" ∼50%) embedded with 15 stacks of AlxGa1-xN/AlyGa1-yN quantum-disks (Qdisks). To improve the carrier injection, a graded layer is introduced at the AlGaN/GaN interfaces on both p- and n-type regions. This work demonstrates a viable approach to easily fabricate ultra-thin, efficient UV optoelectronic devices on low-cost and scalable silicon substrates.
authors.affiliation: King Abdullah University of Science and Technology (KAUST), Photonics Laboratory, Thuwal 23955-6900, Saudi Arabia. Boon.ooi@kaust.edu.sa.
authors.forename: B
authors.initials: B
authors.lastname: Janjua
authors.forename: H
authors.initials: H
authors.lastname: Sun
authors.forename: C
authors.initials: C
authors.lastname: Zhao
authors.forename: D H
authors.initials: DH
authors.lastname: Anjum
authors.forename: F
authors.initials: F
authors.lastname: Wu
authors.forename: A A
authors.initials: AA
authors.lastname: Alhamoud
authors.forename: X
authors.initials: X
authors.lastname: Li
authors.forename: A M
authors.initials: AM
authors.lastname: Albadri
authors.forename: A Y
authors.initials: AY
authors.lastname: Alyamani
authors.forename: M M
authors.initials: MM
authors.lastname: El-Desouki
authors.forename: T K
authors.initials: TK
authors.lastname: Ng
authors.forename: B S
authors.initials: BS
authors.lastname: Ooi