  We report operating temperatures and heating coefficients measured in a
multi-layer black phosphorus device as a function of injected electrical power.
By combining micro-Raman spectroscopy and electrical transport measurements, we
have observed a linear temperature increase up to 600K at a power dissipation
rate of 0.896K\mu m^3/mW. By further increasing the bias voltage, we determined
the threshold power and temperature for electrical breakdown and analyzed the
fracture in the black phosphorus layer that caused the device failure by means
of scanning electron microscopy and atomic force microscopy. The results will
benefit the research and development of electronics and optoelectronics based
on novel two-dimensional materials.
