A breakthrough is reported in the maskless fabrication of flexible photonic crystals based on ultrathin inorganic membranes. Taking into account the concept of Surface Charge Lithography proposed previously [1], a technological route is developed for the fabrication of ultrathin gallium nitride membranes nanoperforated in a controlled fashion. The route is based on direct writing of negative charges on the surface of semiconductor crystalline substrates. Flexible photonic crystals with embedded waveguides, beam splitters etc. are demonstrated and results of modelling of their characteristics are discussed.