Differential photoreflectance from modulation-doped heterojunctions

Abstract
We present a new photoreflectance (PR) technique for studies of layered electronic materials. Using the technique, we isolate the reflected signal from buried interfaces and extract the signature from the two‐dimensional electron gas in high electron mobility transistor. We compare the results from the technique with conventional PR measurements performed on sequentially etched samples. The results indicate that the new technique picks out the PR from buried interfaces and provides data on the in situ electric fields at the interfaces.