Abstract
We have carried out photoreflectance measurements in order to determine the electric field strength FB within the unintentionally doped barriers of Ga-face polarity AlxGa1-xN/GaN heterostructures containing high-mobile polarisation induced 2DEGs. For the sample with both the lowest alloy composition (x = 0.06) and lowest sheet carrier density (ns = 1 × 1012 cm-2) the analysis of the FKO yields FB = 335 kV/cm at RT. FB decreases by 130 kV/cm when cooling down the structure to T = 5 K. In comparison, samples with larger x and ns values show lower field strength at RT but a similar temperature dependence. The results can be explained by a change of piezoelectric polarisation.
| Original language | English |
|---|---|
| Pages (from-to) | 713-716 |
| Number of pages | 4 |
| Journal | Physica Status Solidi (B) Basic Research |
| Volume | 234 |
| Issue number | 3 |
| DOIs | |
| State | Published - Dec 2002 |