title: Direct band gap wurtzite gallium phosphide nanowires.
abstract: The main challenge for light-emitting diodes is to increase the efficiency in the green part of the spectrum. Gallium phosphide (GaP) with the normal cubic crystal structure has an indirect band gap, which severely limits the green emission efficiency. Band structure calculations have predicted a direct band gap for wurtzite GaP. Here, we report the fabrication of GaP nanowires with pure hexagonal crystal structure and demonstrate the direct nature of the band gap. We observe strong photoluminescence at a wavelength of 594 nm with short lifetime, typical for a direct band gap. Furthermore, by incorporation of aluminum or arsenic in the GaP nanowires, the emitted wavelength is tuned across an important range of the visible light spectrum (555-690 nm). This approach of crystal structure engineering enables new pathways to tailor materials properties enhancing the functionality.
authors: Department of Applied Physics, Eindhoven University of Technology, Eindhoven, The Netherlands.
authors: S
authors: S
authors: Assali
authors: I
authors: I
authors: Zardo
authors: S
authors: S
authors: Plissard
authors: D
authors: D
authors: Kriegner
authors: M A
authors: MA
authors: Verheijen
authors: G
authors: G
authors: Bauer
authors: A
authors: A
authors: Meijerink
authors: A
authors: A
authors: Belabbes
authors: F
authors: F
authors: Bechstedt
authors: J E M
authors: JE
authors: Haverkort
authors: E P A M
authors: EP
authors: Bakkers
mesh_terms: D003460:Crystallization; D005708:Gallium / Q000737:chemistry*; D053770:Nanowires / Q000737:chemistry*; D010316:Particle Size; D010720:Phosphines / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry
chemical_list: D010720:Phosphines; C485338:gallium phosphide; D005708:Gallium; D012825:Silicon