Dense and flat freestanding Bi₂Te₃-based thermoelectric nano films were successfully fabricated by sputtering technology using a newly developed nano graphene oxide membrane as a substrate. On-chip micro temperature controllers were integrated using conventional micro-electromechanical system technology, to achieve energy-efficient temperature control for low-power electronics. The tunable equivalent thermal resistance enables an ultrahigh temperature control capability of 100 K mW⁻¹ and an ultra-fast cooling rate exceeding 2000 K s⁻¹, as well as excellent reliability of up to 1 million cycles.