We have shown that stacking fault-free WZ and ZB TSL can be grown by the vapour-liquid-solid (VLS) growth mechanism at a high growth temperature (540 °C). We emphasize that pure WZ and ZB TLS InP NWs were achieved without using dopants. Our WZ and ZB TSL NWs were simultaneously grown for different sizes of gold catalyst seeds, which provides useful input to a more complete understanding of InP NW growth and crystal structure formation.

Importantly, the high growth temperature together with in situ HCl etching to avoid sidewall growth provides high-optical-quality NWs. The WZ NWs do not show any acceptor-related emission, implying that the VLS-grown NW is almost impurity free due to sidewall removal by HCl. They only emit light at the free exciton (1.491 eV) and the donor-bound exciton transition (1.4855 eV) with very narrow linewidths of 1.5–2.0 meV.

The ZB NWs exhibit a PL spectrum that is unaffected by the twinning planes. Surprisingly, the acceptor-related emission in the ZB NWs can be almost completely removed by etching away the impurity-contaminated sidewall grown via a vapour-solid mechanism. The resulting NWs exhibit a long radiative lifetime and a high PL efficiency up to room temperature.

More information can be found in the journal Nanotechnology.