Temperature dependence of mid-infrared intersubband absorption in AlGaN/GaN multiple quantum wells

The temperature dependence of the mid-infrared intersubband (ISB) absorption in non-polar (m-plane) and polar (c-plane) AlGaN/GaN quantum wells (QWs) is studied. The ISB absorption shifts to higher energy as the temperature is reduced from 300K to below 10 K. Both m-plane and c-plane QWs show a small energy shift (1.6-2.6 meV) compared to AlGaAs/GaAs (3.5-5.2meV) and AlSb/InAs (6.2 and 12 meV) QWs. Theoretical calculations considering the temperature induced material constant changes show good agreement with the experimental results. These results suggest that ISB transition energies in AlGaN/GaN QWs are more stable against temperature change mainly because of the heavy effective masses and small nonparabolicities. (C) 2016 AIP Publishing LLC.