Systematic study of near-infrared intersubband absorption of polar and semipolar GaN/AlN quantum wells

Abstract

We report on the observation of intersubband absorption in GaN/AlN quantum well superlattices grown on ð11 22Þ-oriented GaN. The absorption is tuned in the 1:5-4:5 lm wavelength range by adjusting the well thickness. The semipolar samples are compared with polar samples with identical well thickness grown during the same run. The intersubband absorption of semipolar samples shows a significant red shift with respect to the polar ones due to the reduction of the internal electric field in the quantum wells. The experimental results are compared with simulations and confirm the reduction of the polarization discontinuity along the growth axis in the semipolar case. The absorption spectral shape depends on the sample growth direction: for polar quantum wells the intersubband spectrum is a sum of Lorentzian resonances, whereas a Gaussian shape is observed in the semipolar case. This dissimilarity is explained by different carrier localization in these two cases. V C 2013 AIP Publishing LLC [http://dx

Infrared emitters made from III-nitride semiconductors

“…Near-IR ISB absorption has been reported for semipolar (11-22)-oriented GaN/ AlN superlattices (Lahourcade et al , 2008;Machhadani et al , 2013). In comparison to polar QWs, semipolar structures have quasi-square potential band profi les with symmetric wave functions due to the reduced electric fi eld of 0.5-0.6 MV/cm in the QWs.…”

GaN/AlN constant total effective radius multi-wells quantum rings: Physical properties under well number variation effects

“…Experimental growth of AlN/GaN multiple quantum wells by RF plasmaassisted molecular beam epitaxy [22] and experimental [22][23] and theoretical [24] intersubband absorption of this structure with variable total effective length have also been previously done. In the current work we have studied the effect of the number of wells and ring thickness on the refractive index changes, subbandenergies, eigen-functions, Fermi energy of GaN/AlN constant total effective radius multi-wells quantum rings (CTER-MWQRs).…”

Theoretical analysis of modulation doping effects on intersubband transition properties of semipolar AlGaN/GaN quantum well

“…[9][10][11][12] Recently, QW based on nonpolar and semipolar III-nitride materials have emerged as new ISBT structures with improved device performance. 6,[14][15][16][17][18] One major drawback for conventional polar c-plane III-nitride ISBT devices is the large polarization inside the QW, which leads to a quantum-confined Stark effect (QCSE) and a titled QW profile. As a result, the wavelength of the c-plane III-nitride ISBT device is limited.…”