ZnxCd1–xSe/Znx ′Cdy ′Mg1–x ′–y ′ Se multi-quantum well structures for intersubband devices grown by MBE (original) (raw)
Related papers
IEEE Journal of Selected Topics in Quantum Electronics, 2008
Two heavily doped n-type Zn 0 .46 Cd 0 .54 Se/Zn 0 .24 Cd 0 .25 Mg 0 .51 Se multiple quantum well (MQW) structures have been grown on InP (0 0 1) substrates by molecular beam epitaxy. Photoluminescence (PL), time-resolved PL, and Fourier transform infrared (FTIR) spectroscopy were performed to characterize their interband and intersubband (ISB) properties. These two MQW samples have similar structures except for different well widths and a different number of periods. Excitation-intensity-dependent PL shows no electronic coupling between the multiquantum wells. The integrated PL intensities and the PL decay times of the MQWs were measured as functions of temperature in the range from 77 to 290 K. Theoretical fittings of temperature dependences of integrated PL intensities and PL decay times indicate that the nonradiative recombination processes observed in our samples can be well described by hole capture by acceptor-like defect centers through multiphonon emissions. ISB absorption spectra of the samples were measured by FTIR and show peak absorption at wavelengths of 3.99 and 5.35 µm for the MQWs with well widths of 28 and 42Å, respectively. Theoretical calculations based on the envelope function approximation confirm that these peaks are due to the transitions from the ground state E 1 to the first excited state E 2 .
Journal of Vacuum Science & Technology B, 2005
Lattice matched ZnMgSe grown on InP is of considerable interest for its potential applications as a cladding layer due to the high band-gap energy ͑ϳ3.6 eV͒ and for use in intersubband devices such as quantum cascade lasers. Several lattice matched Zn 0.5 Cd 0.5 Se/ Zn 0.13 Mg 0.87 Se quantum wells ͑QWs͒ were grown on InP ͑001͒ substrates. Emission ranging from the near UV to the visible spectral range was achieved by varying the thickness of the wells. The QW fundamental transition as function of the QW thickness was experimentally studied and modeled using an envelope calculation. The contactless electroreflectance measurements of a Zn 0.5 Cd 0.5 Se/ Zn 0.13 Mg 0.87 Se single QW yielded multiple transitions from the QW, allowing us to estimate the conduction band offset of this heterostructure to be as high as 1.12 eV.
A multi-color CdS/ZnSe quantum well photodetector for mid- and long-wavelength infrared detection
Materials Science in Semiconductor Processing, 2014
In this paper, we report on the design and characterization of a quantum well based infrared photodetectors covering simultaneously infrared radiation within mid-and longinfrared spectral regions. The proposed infrared photodetectors rely on intersubband transitions in asymmetric ZnSe/CdS double quantum wells. The three-energy-level and the wavelengths of the intersubband transitions in the asymmetric double quantum wells are obtained by solving the Schrödinger and Poisson equations self consistently, the influence of the right well width on the absorption coefficient is studied. The peak positions of intersubband absorption coefficients in the structure are found at 3.31, 4.4 and 13.5 mm for a 1 nm right well width while the absorption peak positions are located at 3.33, 6.43 and 6.95 mm for a 1.4 nm right well thickness. Then, the electro-optic performances of the infrared photodetector are evaluated; the dark current dependence with the applied voltage and temperature is discussed. This work demonstrates the possibility of detection of widely separated wavelength bands using intersubband transitions in quantum wells with a low dark current.
Intersubband Quantum Well Photodetector ( QWIP )
2002
In recent years photodetectors operating in the midto far infrared region of 3-15μm have been designed based on electron and hole intersubband transitions in multiple quantum wells and superlattices. In general, QWIPs based on electron transitions show greater detectivity compared to the hole-based photodetectors. However, selection rules for electron intersubband transitions usually forbid the TE mode operation, associated with normal light incidence; Therefore, special coupling structures/geometries have been employed to couple light into the device. The spectral region 3-5μm is of interest for a variety of applications such as environmental gas sensing, thermal imaging etc. and is not well covered by existing detectors. We have grown a QWIP operating at ∼3μm with a normal incidence component which incorporates an InGaAs/GaAs asymmetric quantum well from which photo-excited carriers undergo resonant tunnelling into the AlGaAs barriers. A study of temperature-dependent dark current...
Intersubband transitions in molecular-beam-epitaxy-grown wide band gap II-VI semiconductors
Journal of Vacuum Science & Technology B, 2007
The authors report the study of intersubband transitions in ZnCdMgSe-based wide band gap II-VI semiconductors. The samples were prepared by molecular beam epitaxy on InP substrates. Both ZnCdSe/ ZnCdMgSe multiple quantum wells and CdSe/ ZnCdMgSe quantum dot multilayer stacks were grown. Strong intersubband absorption was observed in the samples. The results show that these materials are very promising for fabricating intersubband devices in the mid-and near-infrared spectral ranges.
3 m m Intersubband Quantum Well Photodetector (QWIP)
In recent years photodetectors operating in the mid- to far infrared region of 3-15 m m have been designed based on electron and hole intersubband transitions in multiple quantum wells and superlattices. In general, QWIPs based on electron transitions show greater detectivity compared to the hole-based photodetectors. However, selection rules for electron intersubband transitions usually forbid the TE mode operation, associated with normal light incidence; Therefore, special coupling structures/geometries have been employed to couple light into the device. The spectral region 3-5 m m is of interest for a variety of applications such as environmental gas sensing, thermal imaging etc. and is not well covered by existing detectors. We have grown a QWIP operating at ˜ 3m m with a normal incidence component which incorporates an InGaAs/GaAs asymmetric quantum well from which photo-excited carriers undergo resonant tunnelling into the AlGaAs barriers. A study of temperature-dependent dark...
Nearly lattice-matched Zn1-zCdzSe/Zn1-xCdxSe/Zn1-yMgySe (z > x) quantum wells for yellow emission
Journal of Vacuum Science & Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phenomena, 2016
The authors present the results of the modeling and epitaxial growth of a nearly lattice matched Zn 1-z Cd z Se/Zn 1-x Cd x Se/Zn 1-y Mg y Se quantum well (QW) heterostructure with yellow emission. The ZnCdSe QW is composed of regions with two different Cd content: in the center, seven monolayers of Zn 1-z Cd z Se with z Cd content are surrounded on each side by eight Zn 1-x Cd x Se monolayers with x Cd content (z > x). These last regions are lattice matched to the Zn 1-y Mg y Se barrier. The quantum well design and modeling was based on calculations employing the transfer matrix method. The ZnCdSe quantum well layers were grown in a layer-by-layer mode by submonolayer pulsed beam epitaxy within ZnMgSe barriers grown by molecular beam epitaxy. The low temperature photoluminescence spectrum presented yellow excitonic emission at 2.176 eV, which is in very good agreement with the model calculations. At room temperature, the emission shifted to 2.112 eV, a deep yellow color. V
Growth and Characterization of ZnCdMgSe/ZnCdSe Quantum Wells on InP substrates for Visible Emitters
1999
High-quality lattice-matched quantum well (QW) structures of ZnCdSe/ZnCdMgSe were grown on InP substrates by molecular beam epitaxy. Emission energies from 2.306 to 2.960 eV were measured by low-temperature photoluminescence for samples with QW thicknesses between 5 and 80 Å. Bandgap measurements indicate that these structures could be used in entirely lattice-matched blue, green, and yellow diode laser structures. Experimental measurements indicated that these structures have very little strain; hence, these materials could possibly be less prone to degradation than the Abstract current II-VI blue-green lasers grown on GaAs substrates.
Molecular beam epitaxy and optical properties of ZnCdS/ZnMgS quantum wells on GaP
Journal of Crystal Growth, 2000
We report the growth of ZnCdS/ZnMgS quantum wells (QWs) and their optical properties. The constituent alloy layers were grown by molecular beam epitaxy under a large S #ux and a high substrate temperature. The layers exhibit high quality in terms of double crystal X-ray rocking curve and optical spectra including photoluminescence (PL), PL excitation and re#ection spectra. The ZnCdS/ZnMgS QWs exhibit strong emission from the ZnCdS well(s) through photo-excitation at the ZnMgS barriers. By changing the growth condition of the QW structures, PL line width can be reduced. Such QWs show PL up to room temperature.