  Shot noise of quantum ring (QR) excitons in a p-i-n junction surrounded by a
microcavity is investigated theoretically. Some radiative decay properties of a
QR exciton in a microcavity can be obtained from the observation of the current
noise, which also gives the extra information about one of the tunnel barriers.
Different noise feature between the quantum dot (QD) and QR is pointed out, and
may be observed in a suitably designed experiment.
