Non-volatile memory devices and arrays are described that utilize reverse mode non-volatile memory cells that have band engineered gate-stacks and nano-crystal charge trapping in EEPROM and block erasable memory devices, such as Flash memory devices. Embodiments of the present invention allow a reverse mode gate-insulator stack memory cell that utilizes the control gate for programming and erasure through a band engineered crested tunnel barrier. Charge retention is enhanced by utilization of high work function nano-crystals in a non-conductive trapping layer and a high K dielectric charge blocking layer. The band-gap engineered gate-stack with symmetric or asymmetric crested barrier tunnel layers of the non-volatile memory cells of embodiments of the present invention allow for low voltage tunneling programming and erase with electrons and holes, while maintaining high charge blocking barriers and deep carrier trapping sites for good charge retention.