the 
 iii  v semiconductor ingaas is a key material for photonics 
 because it provides optical emission and absorption in the 1.55 m 
 telecommunication wavelength window . 
 however , ingaas suffers from 
 pronounced nonradiative effects associated with its surface states , 
 which affect the performance of nanophotonic devices for optical interconnects , 
 namely nanolasers and nanodetectors . 
 this work reports the strong 
 suppression of surface recombination of undoped ingaas / inp nanostructured 
 semiconductor pillars using a combination of ammonium sulfide , ( nh4)2s , chemical treatment and silicon oxide , siox , coating . 
 an 80-fold enhancement in the 
 photoluminescence ( pl ) intensity of submicrometer pillars at a wavelength 
 of 1550 nm is observed as compared with the unpassivated nanopillars . 
 the pl decay time of 0.3 m wide square nanopillars 
 is dramatically increased from 100 ps to 25 ns after 
 sulfur treatment and siox coating . 
 the 
 extremely long lifetimes reported here , to our knowledge the highest 
 reported to date for undoped ingaas nanostructures , are associated 
 with a record - low surface recombination velocity of 260 cm / s . 
 we also conclusively show that the siox capping layer plays an active role in the passivation . 
 these results 
 are crucial for the future development of high - performance nanoscale 
 optoelectronic devices for applications in energy - efficient data optical 
 links , single - photon sensing , and photovoltaics .