Characterization, Selection, and Microassembly of Nanowire Laser Systems

Abstract

Semiconductor nanowire (NW) lasers are a promising technology for the realisation of coherent optical sources with extremely small footprint. To fully realize their potential as building blocks in on-chip photonic systems, scalable methods are required for dealing with large populations of inhomogeneous devices that are typically randomly distributed on host substrates. In this work two complementary, high-throughput techniques are combined: the characterisation of nanowire laser populations using automated optical microscopy, and a high accuracy transfer printing process with automatic device spatial registration and transfer. In this work a population of NW lasers is characterised, binned by threshold energy density and subsequently printed in arrays onto 1 arXiv:2001.02032v1 [physics.app-ph] 7 Jan 2020 a secondary substrate. Statistical analysis of the transferred and control devices show that the transfer process does not incur measurable laser damage and the threshold binning can be maintained. Analysis is provided on the threshold and mode spectra of the device populations to investigate the potential for using NW lasers for integrated systems fabrication. KeywordsIII-V Nanowire Lasers, Transfer-Printing, Photoluminescence Nanowire (NW) lasers are ultra-compact, energy efficient sources of coherent light 1 with potential applications ranging from distributed on-chip sensing 2,3 to optical signal processing 4 . A significant amount of effort has been made to optimise the growth processes and physical structure of NW devices to improve brightness, control emission wavelength and modal structure 5,6 . Furthermore, a range of schemes have been developed to integrate these lasers with the necessary on-chip optical components to provide a toolbox to produce future systems. Vertically structured NWs have been directly grown onto silicon waveguide platforms 7 and discrete NW devices have been transferred to host substrates, post-growth, for integration with waveguides 8 , plasmonics 9,10 and complementary NW structures 11 . Typically however, such systems have been proof-of-principle demonstrations of limited numbers of devices, requiring pre-selection of suitable devices and skilled manually controlled microassembly techniques. Nevertheless, pick-and-place assembly is a promising route towards automated fabrication of future systems based on NWs. Future scalable integration of NW devices will have two major requirements, (1) that as-grown NWs can be removed from their growth structure with high yield and (2) that large sets of these devices can be easily characterised before integration to ensure performance matching the application. The transfer of NWs from their growth substrate to a host wafer usually includes a fracturing stage where devices are physically 'snapped' at some point along their length, producing one of the two reflective facets required for lasing 12 . This mechanical process produces popu-

Automated Nanoscale Absolute Accuracy Alignment System for Transfer Printing

“…The alignment method can be slightly modified to allow accurate printing of devices whose position on their native substrate is not defined by lithography, for example, collections of nanowire lasers, 27 nanopillars, and quantum-dot clusters. In these cases the positional referencing of the donor devices must be made by using the devices themselves as registration markers rather than by using separate structures.…”

Applications of Hybrid Metal‐Dielectric Nanostructures: State of the Art

“…[ 217 ] The nanowires are subsequently transferred to the desired substrate by mechanical methods. [ 218 ] For the creation of hybrid metal‐dielectric architectures the target substrate typically features a layered structure (see Figure 11j), which can be obtained by various thin‐film deposition techniques such as evaporation or sputtering. Pre‐structuring of the target substrate can be performed via FIB or EBL‐based techniques (see Figure 11k and l).…”

Tuning nanowire lasers via hybridization with two-dimensional materials

“…[34][35][36][37] Only very recently, such a PDMS-based transfer approach has been successfully used also for NWs. 34,38 In this work, we present a systematic study of the stageassisted transfer technique for NWs that are placed on top of chemical vapor deposition (CVD)-grown MoS 2 ML crystals with micrometer precision. In particular, we focus on the photonic lasing characteristics of MoS 2 monolayer-hybridized ZnO NWs and we demonstrate that the lasing wavelength of ZnO shifts by several nanometers due to interfacial charge transfer and the Moss-Burstein effect.…”