Topic
Band offset
About: Band offset is a research topic. Over the lifetime, 2446 publications have been published within this topic receiving 53450 citations.
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TL;DR: In this paper, the theoretical prediction that the band structures on the opposite sides of a homojunction can be artificially displaced in energy with respect to each other by means of double intralayers of atomiclike thickness was tested.
Abstract: We tested the theoretical prediction that the band structures on the opposite sides of a homojunction can be artificially displaced in energy with respect to each other by means of double intralayers of atomiclike thickness, producing band discontinuities of potential interest for practical applications. Evidence of such discontinuities was found when Ga‐As, Al‐As, Ga‐P, or Al‐P intralayers were inserted between Si and Si or Ge and Ge.
23 citations
TL;DR: In situ monochromatic x-ray photoemission spectroscopy and reflection high-energy electron diffraction were exploited to probe the relation between overlayer orientation, residual strain, and the band discontinuities.
Abstract: CdTe(111)-GaAs(001) and CdTe(001)-GaAs(001) heterostructures were synthesized through molecular-beam epitaxy. In situ monochromatic x-ray photoemission spectroscopy and reflection high-energy electron diffraction, together with ex situ cross-sectional transmission electron microscopy, were exploited to probe the relation between overlayer orientation, residual strain, and the band discontinuities. CdTe(001)-GaAs(001) heterostructures appear fully relaxed even at the lowest overlayer thicknesses explored through the formation of a misfit dislocation network. Correspondingly, the valence-band maximum in the CdTe(001) overlayer is found 0.07--0.09 eV below that of GaAs(001). In CdTe(111)-GaAs(001) heterostructures, we find that residual strains are gradually accommodated within a 200-\AA{}-thick CdTe layer near the interface. The average position of the valence-band maximum in CdTe(111) is 0.09--0.11 eV above that of GaAs(001) at the interface. The difference in valence-band discontinuity for the two interfaces is qualitatively consistent with that expected from the effect of the residual strain on the valence-band maximum of CdTe(111).
23 citations
TL;DR: In this article, the valence band offset of 0.3 eV at the InP/PbSe heterointerface was measured by X-ray Photoelectron Spectroscopy.
22 citations
28 Apr 2005
TL;DR: In this paper, the authors describe the growth and performance of AlInAsSb/AlSb barriers using a 0.3 mole fraction of Al in the Group III elements.
Abstract: For many years, mid-infrared (2-5μm) semiconductor lasers operating at or near room temperature have been sought for use in LADAR, gas sensing, and spectroscopy. Smaller bandgap materials necessary for this range are more susceptible to non-radiative Auger recombination. Further, as laser structures become more complicated, like quantum cascade intersubband and interband lasers, Shockley-Read-Hall losses increase. The simplest structure is Type-I multiple quantum well (MQW), but few QW III-V heterojunction material systems capable of 2-5μm emission have a Type-I offset. One such system with InAsSb wells and AlInAsSb barriers has been unable to exceed 175K under CW operation partially due to poor carrier confinement associated with small valence band offsets. This paper describes the growth and performance of AlInAsSb/InAsSb lasers using a 0.3 mole fraction of Al in the Group III elements. Increased Al content enhances the valence and conduction band offsets, but the AlInAsSb alloy exhibits a miscibility gap above 0.06 Al mole fraction, so a digital alloy technique was used to grow high quality 0.3-2μm thick quaternary films. As Al mole fraction in the barriers was increased from 0.20 to 0.30 an 80-fold increase in photoluminescence (PL) was observed. The corresponding lasers were grown and tested demonstrating lasing at 3.9μm and 50K. Theoretical studies suggest that adding Ga to the barriers, forming an AlGaInAsSb quinary alloy, results in band structures more favorable towards minimizing Auger effects and realizing Type I offset behavior over a wider range of alloy compositions. PL structures were grown and tested, again using a digital alloy technique for the quinary alloy. Preliminary results show promise.
22 citations
TL;DR: In this paper, the authors report on the material and electrical characterizations of high dielectric constant (k) oxide HfTiAlO for the next generation of complementary metal-oxide semiconductors.
Abstract: In this letter, the authors report on the material and electrical characterizations of high dielectric constant (k) oxide HfTiAlO for the next generation of complementary metal-oxide semiconductors. Crystallization temperature has been improved to 800–900°C versus that of HfO2. The substitution of Ti and Al in the HfO2 cubic structure results in an increased dielectric constant and an acceptable barrier height. The extracted dielectric constant is 36, and the band offset relative to the Si conduction band is 1.3eV. An equivalent oxide thickness of 11A and low leakage have been achieved with good interfacial properties.
22 citations