Fundamentals of charge storage in acoustic charge transport devices

Double-packet storage is demonstrated for the first time, and the properties of single-packet and double-packet storage are compared. Double-packet storage is found to provide higher storage capacity with less storage voltage than single-packet storage. For the same SAW (surface acoustic wave) frequency, however, double-packet storage has half the bandwidth of single-packet storage. Intercell diffusion is a key factor that limits the storage capacity of single-packet storage, but it is not a key limiting factor for double-packet storage. Surface extraction can be a significant limiting factor for single-packet storage, if the doping level is too low. It was not found to be a significant factor for double-packet storage. The primary factor limiting the storage capacity of double-packet storage is the delay-line charge capacity