Intersubband transitions in ZnO multiple quantum wells

Intersubband transitions in ZnO∕MgZnO multiple quantum wells (MQWs) are investigated by a photocurrent spectroscopy. Photocurrent peaks are observed in the energy range from 300to400meV and shifted to higher energy by reducing the ZnO well thickness. Polarization-resolved photocurrent spectra show that these peaks are observed when the polarization of incident lights is TM mode, following the intersubband selection rule. Calculation indicates that the photocurrent peaks are the intersubband transition from the first to the third subband in ZnO∕MgZnO MQWs.

[1]  H. Ohno,et al.  Repeated temperature modulation epitaxy for p-type doping and light-emitting diode based on ZnO , 2004 .

[2]  Shun Lien Chuang,et al.  k.p method for strained wurtzite semiconductors , 1996 .

[3]  Akira Ohtomo,et al.  MgxZn1−xO as a II–VI widegap semiconductor alloy , 1998 .

[4]  H. Ohno,et al.  Surface morphologies of homoepitaxial ZnO on Zn- and O-polar substrates by plasma assisted molecular beam epitaxy , 2006 .

[5]  J. Massies,et al.  Barrier-width dependence of group-III nitrides quantum-well transition energies , 1999 .

[6]  Raphael Tsu,et al.  Superlattice and negative differential conductivity in semiconductors , 1970 .

[7]  Masashi Kawasaki,et al.  Ultraviolet spontaneous and stimulated emissions from ZnO microcrystallite thin films at room temperature , 1997 .

[8]  Masashi Kawasaki,et al.  Quantum Hall Effect in Polar Oxide Heterostructures , 2007, Science.

[9]  Erich P. Ippen,et al.  Feasibility of 1.55 µ m Intersubband Photonic Devices Using InGaAs/AlAs Pseudomorphic Quantum Well Structures , 1994 .

[10]  K. Bajaj,et al.  Excitonic transitions in ZnO/MgZnO quantum well heterostructures , 2001 .

[11]  P. Lefebvre,et al.  Internal electric field in wurtzite Zn O ∕ Zn 0.78 Mg 0.22 O quantum wells , 2005 .

[12]  Observation of Intersubband Transition from the First to the Third Subband (e1–e3) in GaN/AlGaN Quantum Wells , 2002 .

[13]  J. M. Kuo,et al.  Photoexcited escape probability, optical gain, and noise in quantum well infrared photodetectors , 1992 .

[14]  Akira Ohtomo,et al.  Band gap engineering based on MgxZn1−xO and CdyZn1−yO ternary alloy films , 2001 .

[15]  T. Makino,et al.  Optical properties of excitons in ZnO-based quantum well heterostructures , 2004 .

[16]  Zikang Tang,et al.  Room-temperature stimulated emission of excitons in ZnO/(Mg, Zn)O superlattices , 2000 .