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Self-planarized quantum-disks-in-nanowires ultraviolet-B emitters utilizing pendeo-epitaxy

2017; Royal Society of Chemistry; Volume: 9; Issue: 23 Linguagem: Inglês

10.1039/c7nr00006e

2040-3372

Bilal Janjua, Haiding Sun, Chao Zhao, Dalaver H. Anjum, Feng Wu, Abdullah A. Alhamoud, Xiaohang Li, Abdulrahman Albadri, Ahmed Y. Alyamani, Munir M. El‐Desouki, Tien Khee Ng, Boon S. Ooi,

ZnO doping and properties

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.