Piezoelectric energy harvesters are devices that power sensor nodes and generally low-power electronics. This is achieved by converting vibrations or alternating magnetic fields into electrical power stored in a secondary cell. Most of the piezoelectric energy harvesters are based on cantilevers as they have lower resonant frequencies which allows to gather widespread energy sources present at low frequencies (<100 [Hz]). The vast majority of piezoelectric energy harvesters use silicon as the base material for the cantilever’s structure. However, silicon is a fragile material that breaks easily for larger deformations which limits the reliability of the devices. Moreover, the majority of the previous studies do not take into consideration the energy conversion circuit which rectifies and adapts the electrical load. In the present work, simulations were realized with COMSOL to assess the electrical power generation. Moreover, simulations of the electrical conversion circuits were performed to evaluate the efficiency of SSHI and FBR electrical circuits. Finally, SU-8 was investigated as an alternative to silicon as the cantilever’s structural material. A SU-8 shim was thus fabricated using MEMS cleanroom processes and the cantilevers were released through dry etching. The simulation results obtained in this thesis indicate that SU-8 cantilevers combined with an AlScN 40%piezoelectric layer increase the power output compared to silicon cantilevers at equivalent excitation levels. Moreover, the electrical circuit simulations depict that SSHI circuits increase the power output compared to FBR circuits only when the input excitation exceeds a certain threshold. Finally, this work demonstrated for the first time in the CMi cleanroom the possibility of releasing SU-8 through backside dry etching.