Abstract
Nanolasers hold promise for applications including integrated photonics, on-chip optical interconnects and optical sensing. Key to the realization of current cavity designs is the use of nanomaterials combining high gain with high radiative efficiency. Until now, efforts to enhance the performance of semiconductor nanomaterials have focused on reducing the rate of non-radiative recombination through improvements to material quality and complex passivation schemes. Here we employ controlled impurity doping to increase the rate of radiative recombination. This unique approach enables us to improve the radiative efficiency of unpassivated GaAs nanowires by a factor of several hundred times while also increasing differential gain and reducing the transparency carrier density. In this way, we demonstrate lasing from a nanomaterial that combines high radiative efficiency with a picosecond carrier lifetime ready for high speed applications.
Highlights
Nanolasers hold promise for applications including integrated photonics, on-chip optical interconnects and optical sensing
The GaAs NWs investigated in this work were grown by metal-organic vapour phase epitaxy at a relatively high temperature (575 °C) and low V/III ratio (1.4)
Zinc-doping leads to a transformation from a pure wurtzite crystal structure (Fig. 1a–d) to a zincblende twining superlattice (TSL) structure (Fig. 1f-i; a high magnification transmission electron microscopy (TEM) image of the TSL structure is shown in Supplementary Fig. 1)[33]
Summary
Nanolasers hold promise for applications including integrated photonics, on-chip optical interconnects and optical sensing. We employ controlled impurity doping to increase the rate of radiative recombination This unique approach enables us to improve the radiative efficiency of unpassivated GaAs nanowires by a factor of several hundred times while increasing differential gain and reducing the transparency carrier density. In this way, we demonstrate lasing from a nanomaterial that combines high radiative efficiency with a picosecond carrier lifetime ready for high speed applications. Previous reports have achieved reductions in radiative lifetime through the Purcell effect by coupling emitters to a resonant cavity[29,30,31,32] In contrast to these works, we employ impurity doping, which acts to directly increase radiative efficiency without the need for further fabrication steps. The resultant GaAs NWs combine excellent radiative efficiency with an ultrashort lifetime and deliver superior room temperature lasing performance relative to undoped, surface passivated GaAs/AlGaAs heterostructure NWs
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