Near-infrared intersubband absorption in GaN/AlN quantum wells grown by molecular beam epitaxy

Abstract

GaN/AlN multiple-quantum-well structures were grown by molecular beam epitaxy. Abrupt interfaces and good periodicity were confirmed. Absorption measurements indicated that intersubband absorptions occurred at wavelengths of 1.3–2.2 μm. Spectral fits by Lorentzians suggested that the well thicknesses fluctuated by two monolayers. The linewidths of the individual fits were as narrow as 80–120 meV. The characteristics of the absorption saturation were investigated at a wavelength of 1.46 μm. A relaxation time of 400 fs and saturation energy density of 0.5 pJ/μm2 were obtained. These results are promising for realizing ultrafast optical switches with energy consumption of the picojoule order.

Crack Free GaInN/AlInN Multiple Quantum Wells Grown on GaN with Strong Intersubband Absorption at 1.55μm

“…They are also interesting in sense of low-dimensional semiconductor physics. In nitrides, due to enhanced electron-phonon interaction in these highly ionic materials, IS absorption recovery times are extremely short, it means that they are typically of the order of 150-400 fs [4,8,9]. In nitrides, one can find a few possibilities to fabricate very deep quantum well, where electron band-gap discontinuity is more than 1 eV.…”

Latest developments in GaN-based quantum devices for infrared optoelectronics

“…Material systems with large enough conduction band offsets to accommodate ISB transitions at relatively short wavelengths (1.3, 1.55 lm) include InGaAs/AlAsSb [14] (CdS/ZnSe)/BeTe [2], and GaN/AlGaN QWs [11,12,17,26,32,36,37]. A specific advantage of III-nitrides is their extremely short ISB absorption recovery times (*150-400 fs [16,22,23]) due to the strong electron-phonon interaction in these materials, which open the way to devices operating in the 0.1-1 Tbit/s bit-rate regime. Furthermore, the wide bandgap of nitride semiconductors prevents two-photon absorption in the near-infrared, and devices would profit from other advantages of nitride technology, such as high power handling and chemical and thermal robustness.…”

MBE growth of AlN/GaN‐based photovoltaic intersubband photodetectors

“…Furthermore, the remote lateral valleys lie very high in energy (>2 eV) above the Γ valley, which is a key feature to achieve ISB lasing. Finally, devices would profit from other advantages of nitride technology, such as high power handling capabilities and chemical and thermal robustness.In the last few years, various groups have reported ISB absorption at 1.3-1.55 µm in GaN/Al(Ga)N nanostructures in the form of QWs [1][2][3][4][5] or quantum dots [6]. The…”

“…In the last few years, various groups have reported ISB absorption at 1.3-1.55 µm in GaN/Al(Ga)N nanostructures in the form of QWs [1][2][3][4][5] or quantum dots [6]. The…”