The b-unstable nuclei 32,34,36,38 Si have been produced by projectile fragmentation and studied by inbeam Coulomb excitation. Excited states at 1399 6 25 keV and 1084 6 20 keV have been identified for the first time in 36 Si and 38 Si, respectively, and tentatively assigned J p 2 1 . The B͑E2; 0 1 1 ! 2 1 1 ͒ values leading to these states and the previously identified 2 1 1 states in 32,34 Si have been measured, and are compared to shell model calculations. Our results indicate that the 2 1 1 state in 34 Si has a large fp-shell intruder component, and that the 2 1 1 states in the N . 20 silicon isotopes can be reproduced assuming an N 20 shell closure. [S0031-9007(98)