Overcoming Auger recombination in nanocrystal quantum dots using Purcell enhancement

Chemically synthesized semiconductor nanocrystal quantum dots (NQDs) are promising candidates for gain media in micro/nano-lasers. The key advantage of using these NQDs is wide-tunability of emission wavelength across the visible and near IR spectrum [1], which is achieved by synthesizing NQDs of different sizes. One well-known decay process, which becomes significant with size reduction in NQDs, is non-radiative Auger recombination, and it has been identified as the main hindrance in achieving lasing with NQDs [2]. Lasing has been demonstrated in a variety of low-loss microcavities with moderate spatial confinement [3][4], by employing close-packed films of NQDs - a way to overcome Auger recombination process. Here we show that by using moderate-loss cavities that provide strong spatial confinement, which results in Purcell enhancement [5], we can overcome Auger recombination process, and achieve efficient lasing with only a few hundreds of NQDs.