The forward voltage of Si and GaAlAs diodes have been studied in the temperature range 10-300 K and for various current values (10 nA to 0.5 mA). The temperature sensitivity of these diodes have been obtained. Flicker 1/f noise has been observed in the GaAlAs diode. Possible use of GaAlAs diode for measurement of mK temperatures has been suggested. For Si diode the ÂreducedÂ forward voltage at T=0 is found to be 1.0 V.