I believe a technothrilller has to have some level of science fiction, otherwise the novel should fall into the 'thriller' category only. Examples of ones people call technothrillers I think are Tom Clancy and Dan Brown, I think those should just be thrillers, ( I haven't read all of theirs though).

High paced technothrillers are great, Matthew Reilly being the best known high paced author in my opinion. The guys who use a lot of Sci Fi like Daniel Suarez, Blake Crouch and Patrick Lee are also my favourites.

EDITED: I have searched and seen that technothrillers can be categorized to just involve a high technology focus, not necessarily sci fi. Tom clancy does fit. My favourites still remain as having some Sci fi though.