my professor asked me to use this specific MOSFET! I guess because I'm working with a 5 Amps converterYour datasheet link did not post properly; here it is:
http://www.irf.com/product-info/datasheets/data/irf9540ns.pdf
Can you tell us the reasons/selection criteria why you chose that particular MOSFET?
Why a P-channel instead of an N-channel?
Why that high of a Vdss?