Hawking radiation is viewed as a tunnelling process. In this way the effect of self-gravitation gives rise to semiclassical corrections to the entropy of the (2+1) BTZ black hole. The modified entropy, due to specific modelling of the self-gravitation effect, of the (2+1) BTZ black hole is evaluated. To first order in $\omega$ which is a shell of energy radiated outwards the event horizon of the BTZ black hole, modified entropy is proportional to the horizon. In this semiclassical analysis, corrections to the Bekenstein-Hawking formula $S_{ BH}=\mathcal{ A}_{ H} / 4l_{ P}^{ 2}$ are found to be negative and the proportionality factor connecting the modified entropy, $S_{ bh}$, of the (2+1) BTZ black hole to the Bekenstein-Hawking entropy, $S_{ BH}$, is evaluated to first order in $\omega$.
Categories: hep-th gr-qc