Effect of delta doping on mid-infrared intersubband absorption in AlGaN/GaN step quantum well structures

• The effects of delta-doping on mid-infrared intersubband (ISB) absorption in AlGaN/GaN SQWs have been theoretically studied.
• Delta-doping is found holding advantage over uniform-doping in mid-infrared ISB absorption.
• ISB absorption widths and peak values significantly depend on the doping concentration, but not on the doping location.
• The broadening of spectral lineshapes with higher doping density is attributed to the higher electron–electron scattering rate.

We present an ensemble Monte Carlo simulation to investigate the dynamics of electrons in 3-level AlGaN/GaN step quantum wells (SQW), which are potentially interesting for the development of mid-infrared optically pumped intersubband (ISB) terahertz lasers. Through comparison, delta-doping is found holding advantage over uniform-doping in mid-infrared ISB absorption. We demonstrate that ISB absorption widths and peak values significantly depend on the doping concentration, but not on the doping location. The broadening of spectral lineshapes with higher doping density is attributed to the higher electron–electron scattering rate.