Low-threshold ultraviolet stimulated emissions from large-sized single crystalline ZnO transferable membranes.
Opt Express
; 26(24): 31965-31975, 2018 Nov 26.
Article
em En
| MEDLINE
| ID: mdl-30650775
ABSTRACT
Wide-bandgap inorganic semiconductors based ultraviolet lasers bring versatile applications with significant advantages including low-power consumption, high-power output, robustness and long-term operation stability. However, flexible membrane lasers remain challenging predominantly due to the need for a lattice matched supporting substrate. Here, we develop a simple laser liftoff process to make freestanding single crystalline ZnO membranes that demonstrate low-threshold ultraviolet stimulated emissions together with large sized dimension (> 2 mm), ultralow-weight (m/A<15 g/m2) and excellent flexibility. The 2.6 µm-thick crack-free ZnO membrane exhibits well-retained single crystallinity and enhanced excitonic emissions while the defect-related emissions are completely suppressed. The inelastic exciton-exciton scattering stimulated emissions with increased spontaneous emission rate is obtained with a reduced threshold of 0.35 MW/cm2 in the ZnO membrane transferred onto a flexible polyethylene naphthalate substrate. Theoretical simulations reveal that it is a synergetic effect of the increased quantum efficiency via Purcell effect and the improved optical gain due to vertical directional waveguiding of the membrane, which functions as a Fabry-Perot photonic resonator due to the refractive index contrast at ZnO-air boundaries. With simple architecture, efficient exciton recombination and easy fusion with waveguide system, the ZnO membranes provide an alternative platform to develop compact low-threshold ultraviolet excitonic lasers.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Opt Express
Assunto da revista:
OFTALMOLOGIA
Ano de publicação:
2018
Tipo de documento:
Article