  A thermocouple of Au-Ni with only 2.5-micrometers-wide electrodes on a
30-nm-thick Si3N4 membrane was fabricated by a simple low-resolution electron
beam lithography and lift off procedure. The thermocouple is shown to be
sensitive to heat generated by laser as well as an electron beam. Nano-thin
membrane was used to reach a high spatial resolution of energy deposition and
to realise a heat source of sub-1 micrometer diameter. This was achieved due to
a limited generation of secondary electrons, which increase a lateral energy
deposition. A low thermal capacitance of the fabricated devices is useful for
the real time monitoring of small and fast temperature changes, e.g., due to
convection, and can be detected through an optical and mechanical barrier of
the nano-thin membrane. Temperature changes up to ~2x10^5 K/s can be measured
at 10 kHz rate. A simultaneous down-sizing of both, the heat detector and heat
source strongly required for creation of thermal microscopy is demonstrated.
Peculiarities of Seebeck constant (thermopower) dependence on electron
injection into thermocouple are discussed. Modeling of thermal flows on a
nano-membrane with presence of a micro-thermocouple was carried out to compare
with experimentally measured temporal response.
