Confirmation of the pyroelectric coefficient of strained In_xGa_1-xAs/GaAs quantum well structures grown on (111)B GaAs by differential photocurrent spectroscopy

In this work we used the differential photocurrent technique to measure the strain-induced piezoelectric field in pseudomorphic In_xGa_1-xAs/GaAs heterostructures grown by molecular beam epitaxy on (111)B GaAs substrates. Single and multiple quantum well p–i–n diodes with two different In fractions in the well were analyzed in the temperature range of 25–300 K. Our results for a sample with a 17% In fraction confirm the previously reported value of the pyroelectric coefficient for a similar sample obtained by photoreflectance spectroscopy, hence, the equivalence of the differential photocurrent and photoreflectance techniques is also demonstrated. For a sample with 21% In, we report experimental determination of the temperature dependence of the piezoelectric constant and, therefore, of the strain-induced component of the pyroelectric coefficient. © 2002 American Institute of Physics.