Study on the temperature sensing capability of a light-emitting diode

A study on the temperature sensing capability of a light-emitting diode (LED) has been made. Dependence of I-V characteristics as a function of temperature is used as a temperature sensing mechanism. It is found that the temperature voltage characteristics of a GaP LED are quite linear from 77 to 533 K. The measured sensitivity of the diode is 5.31 mV/K at 1 pA and is 2.34 mV/K at 0.1 mA. Since the reverse saturation current of LED is less than fempto-ampere range, it is possible to operate the thermometer at low currents, as compared to silicon or germanium diode thermometers, which reduce power dissipation in the device. It has been possible to extend the temperature range to higher value due to large value of band gap for LEDs. (C) 1997 American Institute of Physics.