  We present semi-analytical models of high redshift Lyman-{\alpha} emitters
(LAEs) in order to constrain the star formation efficiency in those galaxies.
Our supernova feedback induced star formation model along with Sheth-Tormman
halo mass function correctly reproduces the shape, amplitude and the redshift
evolution of UV and Lyman-{\alpha} luminosity functions of LAEs in the redshift
range z = 2 to 7.3. We show that the fraction of Lyman-{\alpha} emitting
galaxies increases with increasing redshifts reaching to unity just after the
reionisation. However, we show that star formation efficiency in those LAEs
does not show any redshift evolution within the uncertainty in available
observations. This would have significant repercussion on the reionisation of
the intergalactic medium.
