At young ages, low surface gravity affects the atmospheric properties of ultracool dwarfs. The impact on medium-resolution near-infrared (NIR) spectra has only been slightly investigated at the M-L transition sofar. We present a library of near-infrared (1.1-2.45um) medium-resolution (R~1500-2000) integral field spectra of 15 young M6-L0 dwarfs. We aim at deriving updated NIR spectral type, luminosity and physical parameters (Teff, logg, M, L/L_{sun}_) of each source. This work also aims at testing the latest generation of BT-SETTL atmospheric models. We estimated spectral types using spectral indices and spectra of reference young objects classified in the optical. We used the 2010 and 2012 releases of the BT-SETTL synthetic spectral grid and cross-checked the results with the DRIFT-PHOENIX models to derive the atmospheric properties of the sources.