Study of two-subband population in Fe-doped AlxGa1-xN/GaN heterostructures by persistent photoconductivity effect
POSTER
Abstract
The electronic properties of Fe-doped Al$_{0.31}$Ga$_{0.69}$N/GaN heterostructures have been studied by Shubnikov-de Haas measurement. The lowest two subbands of the two-dimensional electron gas in the heterointerface were populated. After the low temperature illumination, the electron density increases from 11.99x10$^{12}$ cm$^{-2}$ to 13.40x10$^{12}$ cm$^{-2}$ for the first subband and from 0.66x10$^{12}$ cm$^{-2}$ to 0.94x10$^{12}$ cm$^{-2}$ for the second subband. The persistent photoconductivity effect ($\sim $13{\%} increase) is mostly attributed to the Fe-related deep-donor level in GaN layer. The second subband starts to populate when the first subband is filled at a density of 9.40x10$^{12}$ cm$^{-2}$. We obtained the energy separation between the first and second subbands to be 105 meV.
*This project is supported in part by National Research Council of Taiwan and NRC Core Facilities Laboratory for Nanoscience and Nanotechnology in Kaohsiung-Pingtung Area.