Holistic Nanowire Laser Characterization as a Route to Optimal Design

摘要

Nanowire lasers are sought for near-field and on-chip photonic applicationsas they provide integrable, coherent, and monochromatic radiation:the functional performance (threshold and wavelength) is dependent onboth the opto-electronic and crystallographic properties of each nanowire.However, scalable bottom-up manufacturing techniques often suffer frominter-nanowire variation, leading to differences in yield and performancebetween individual nanowires. Establishing the relationship betweenmanufacturing controls, geometric and material properties, and the lasingperformance is a crucial step toward optimisation; however, this is challengingto achieve due to the interdependance of such properties. Here,a high-throughput correlative approach is presented to characterise over5000 individual GaAsP/GaAs multiple quantum well nanowire lasers. Fittingthe spontaneous emission provides the threshold carrier density, whilecoherence length measurements determine the end-facet reflectivity. Theperformance is intrinsically related to the width of a single quantum welldue to quantum confinement and bandfilling effects. Unexpectedly, thereis no strong relationship between the properties of the lasing cavity andthe threshold: instead the threshold is negatively correlated with the nonradiativerecombination lifetime of the carriers. This approach thereforeprovides an optimisation strategy that is not accessible through small-scalestudies.