| dc.description.abstract | InGaAs/InP single photon avalanche diodes are of great potential in the
application of near-infrared optical fiber communication. However, comparing
to Si single photon avalanche diodes, InGaAs/InP single photon avalanche
diodes have higher dark count due to its material and structural characteristics.
In this thesis, we characterize the dark count performance at different
temperature ranges by operating the device under gated mode with frequency of
10 kHz and voltage pulse width of 20 ns. The device is cooled down to 77 K by
using liquid nitrogen. From the experiments, different mechanisms are dominant
over different temperature ranges. In high temperature region (200 K-300 K),
the dark counts originate from the thermal generation. For the low temperature
region (77 K-125 K), afterpulsing dominates. While in the intermediate
temperature region (125 K-200 K), the dark count rates should be restricted to
the tunneling carriers, however, a non-monotonic behavior in the dark count
performance is observed, that is, a local maximum of dark count rates occurs at
around 150 K. In order to study this phenomenon, we vary the internal electric
field and found that the local maximum shifts to lower temperature, showing
that the local maximum is sensitive to the internal electric field and hence is
attributed to the charge persistence effect.
To further evidence this argument, we illuminate the device with a
time-varying incoming pulse laser. It is found that the charge persistence effect
gets most serious at 150 K, where the local maximum of dark count rate occurs.
At 200 K, where the thermal carriers are greatly suppressed, the device is almost
free from the charge persistence effect. The investigation reflects that the charge
persistence effect is involved in the intermediate temperature rage and it is
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caused not only by the photo-generated carriers but also by the
thermal-generated carriers. We also attempt to see the impact of charge
persistence effect on the photon detection efficiency. Our results reveal that the
photon detection efficiency could be overestimated due to the existence of
charge persistence effect. | en_US |