  Single-photon sources are key building blocks in most of the emerging secure
telecommunication and quantum information processing schemes. Semiconductor
quantum dots (QD) have been proven to be the most prospective candidates.
However, their practical use in fiber-based quantum communication depends
heavily on the possibility of operation in the telecom bands and at
temperatures not requiring extensive cryogenic systems. In this paper we
present a temperature-dependent study on single QD emission and single-photon
emission from metalorganic vapour-phase epitaxy-grown InGaAs/GaAs QDs emitting
in the telecom O-band. Micro-photoluminescence studies reveal that trapped
holes in the vicinity of a QD act as reservoir of carriers that can be
exploited to enhance photoluminescence from trion states observed at elevated
temperatures up to at least 80 K. The luminescence quenching is mainly related
to the promotion of holes to higher states in the valence band and this aspect
must be primarily addressed in order to further increase the thermal stability
of emission. Photon autocorrelation measurements yield single photon emission
with a purity of $g_{50\mathrm{K}}^{(2)}\left(0\right)=0.13$ up to 50 K. Our
results imply that these nanostructures are very promising candidates for
single-photon sources at elevated temperatures in the telecom O-band and
highlight means for improvements in their performance.
