A study of forward characteristics of a GaAlAs temperature sensor diode

The forward characteristics of a cryogenic GaAlAs temperature sensor diode (Lake Shore Cryotronics, Inc) in the temperature range 10-300 K and for fix ed currents between 10 nA and 500 mu A have been presented. The upturn in t he forward characteristic below 35 K was found to be shifted to lower tempe ratures on reducing the current. The sensitivity at low temperature was fou nd to reduce with current (I) according to a power law. The sensitivity at high temperature was found to increase linearly with decreasing log(I). We suggest the use of a current of less than 10 mu A, which has the advantage of reducing Joule power dissipation and improving high temperature sensitiv ity and linearity.