We report results on hexagonal-shaped microlasers formed from two-dimensional photonic crystals (PCs) using InP-based materials transferred and bonded onto SiO2/Si wafers. Two types of hexagonal cavities are investigated : single defect (one hole missing) cavities, so-called H1 cavities (1 mum in diameter) and two holes missing per side H2 cavities (2 mum in diameter). Their optical properties are analyzed using photoluminescence experiments, and plane wave method simulations have been performed for comparison. High Q modes (similar to600/700) have been measured and they have been shown to enable laser effect at room temperature, under pulsed optical pumping (15% duty cycle and 25-ns pulsewidth). The study of these efficient mode characteristics gives guidance for further improvement of the operation conditions of PC lasers, such as the reduction of the threshold pumping power.