Growth of κ-([Al,In] x Ga1-x)2O3 Quantum Wells and Their Potential for Quantum-Well Infrared Photodetectors

The wide band gap semiconductor kappa-Ga2O3 and its aluminum and indium alloys have been proposedas promisingmaterials for many applications. One of them is the use of inter-sub-bandtransitions in quantum-well (QW) systems for infrared detectors. Oursimulations show that the detection wavelength range of nowadays stateof the art GaAs/Al x Ga1-x As quantum-well infrared photodetectors (QWIPs) couldbe substantially excelled with about 1-100 mu m using kappa-([Al,In]( x )Ga1-x )(2)O-3, while at the same time being transparent tovisible light and therefore insensitive to photon noise due to itswide band gap, demonstrating the application potential of this materialsystem. Our simulations further show that the QWIPs efficiency criticallydepends on the QW thickness, making a precise control over the thicknessduring growth and a reliable thickness determination essential. Wedemonstrate that pulsed laser deposition yields the needed accuracy,by analyzing a series of (In x Ga1-x )(2)O-3 QWs with (Al y Ga1-y )(2)O-3 barriers with high-resolution X-ray diffraction, X-rayphotoelectron spectroscopy (XPS) depth profiling, and transmissionelectron microscopy (TEM). While the superlattice fringes of high-resolutionX-ray diffraction only yield an average combined thickness of theQWs and the barrier and X-ray spectroscopy depth profiling requireselaborated modeling of the XPS signal to accurately determine thethickness of such QWs, TEM is the method of choice when it comes tothe determination of QW thicknesses.