  Miniaturized or even microscale generators that could effectively and
persistently converse weak and random mechanical energy from environments into
electricity promise huge applications in the internet of things, sensor
networks, big data, personal health systems, artificial intelligence, etc.
However, such generators haven't appeared yet because either the current
density, or persistence, or both of all reported attempts were too low to real
applications. Here, we demonstrate a superlubric Schottky generator (SLSG) in
microscale such that the sliding contact between a microsized graphite flake
and an n-type silicon is in a structural superlubric state, namely a ultralow
friction and wearless state. This SLSG generates a stable electrical current at
a high density (~119 Am-2) for at least 5,000 cycles. Since no current decay
and wear were observed during the entire experiment, we believe that the real
persistence of the SLSG should be enduring or substantively unlimited. In
addition, the observed results exclude the mechanism of friction excitation in
our Schottky generator, and provide the first experimental support of the
conjectured mechanism of depletion layer establishment and destruction (DLED).
Furthermore, we demonstrate a physical process of the DLED mechanism by the use
of a quasi-static semiconductor finite element simulation. Our work may guide
and accelerate future SLSGs into real applications.
