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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05 Dec 1994
TL;DR: In this paper, a pseudomorphic GaAsSb layer was employed to obtain a band alignment at a InGaAs or InAlAs p-n junction favorable for forward bias tunneling.
Abstract: We report a new approach to tunnel junctions that employs a pseudomorphic GaAsSb layer to obtain a band alignment at a InGaAs or InAlAs p-n junction favorable for forward bias tunneling. Since the majority of the band offset between GaAsSb and InGaAs or InAlAs is in the valence band, when an GaAsSb layer is placed at an InGaAs or InAlAs p-n junction the tunneling distance is reduced and the tunneling current is increased. For all doping levels studied, the presence of the GaAsSb-layer enhanced the forward tunneling characteristics. In fact, in a InGaAs/GaAsSb tunnel diode with p=1.5/spl times/10/sup 18/ cm/sup -3/ a peak tunneling current sufficient for a 1000 sun InP/InGaAs tandem solar cell interconnect was achieved while a similarly doped all-InGaAs diode was rectifying. This approach affords a new degree of freedom in designing tunnel junctions for tandem solar cell interconnects. Previously only doping levels could be varied to control the tunneling properties. Our approach relaxes the doping requirements by employing a GaAsSb-based heterojunction.
16 citations
TL;DR: In this article, the effect of nitrogen incorporation on polyatomic layer chemical vapor deposition (PLCVD) hafnium silicate (HfSixOy) films was investigated.
Abstract: The effect of nitrogen incorporation on polyatomic layer chemical vapor deposition (PLCVD) hafnium silicate (HfSixOy) films was investigated The physical and electrical properties of nitride hafnium silicate (HfSixOyNz) and HfSixOy dielectric films are reported X-ray photoelectron spectroscopy (XPS) was used to check chemical compositions, nitrogen profile, band gap, and band offset of the HfSixOy and HfSixOyNz films The nitrogen incorporation results in decreases in the band gap and band offset of the HfSixOy sample The nitrogen profile obtained by secondary ion mass spectroscopy (SIMS) shows a gradient decrease from the surface to the interface The prepared HfSixOy and HfSixOyNz films have reasonable electrical performance
16 citations
01 Jan 1985
TL;DR: The energy band structure is the relationship between the energy and momentum of a carrier in a solid as discussed by the authors, and it is the most common way to measure the energy of an electron in free space, where energy is proportional to the square of the momentum.
Abstract: The energy band structure is the relationship between the energy and momentum of a carrier in a solid. For an electron in free space, the energy is proportional to the square of the momentum. The factor of proportionality is 1/2 m 0, where m 0 is the free electron mass. In the simple model of band structure, the same relationship between energy and momentum is assumed except that m 0 is replaced by an effective mass m. This may be larger or smaller than m 0 . Why this is so will be seen later in this chapter. Quite often the band structure is more complex and can only be calculated semi-empirically even with computers. A short description of some typical band structures will be given in Sect. 2.4 and used for the calculation of charge transport in Chaps. 7, 8, while in Chaps. 4, 5, the transport properties will be calculated assuming the simple model of band structure (which is quite a good approximation for most purposes).
16 citations
TL;DR: A combination of transmission electron microscopy and high-resolution x-ray diffraction analyses has been used to determine the exact strain in each layer of InAsP/InP multiple-quantum-well structures grown by metalorganic vapor phase epitaxy on InP(001) using trimethylindium, tertiary butylarsine, and phosphine as precursors.
Abstract: A combination of transmission electron microscopy and high‐resolution x‐ray diffraction analyses has been used to determine the exact strain in each layer of InAsP/InP multiple‐quantum‐well structures grown by metalorganic vapor phase epitaxy on InP(001) using trimethylindium, tertiarybutylarsine, and phosphine as precursors. The strain‐relaxed structures are characterized by misfit dislocations located exclusively at (i) the interface between the buffer layer and the multilayer, and (ii) the interface between the multilayer and the cap layer. The low‐temperature optical absorption spectra show well resolved excitonic transitions that are significantly shifted by strain relaxation. The spectra are analyzed with a solution to the Schrodinger equation in the envelope function formalism using the Bastard–Marzin model. The energies for the major transitions involving light‐ and heavy‐holes are predicted accurately for all samples, allowing the determination of the heterojunction band offset. The heavy‐ and li...
16 citations
TL;DR: In this paper, the energy band structure of 4H-SnS2 was calculated using the local pseudopotential method in such a way that a direct comparison can be made with the 2H-snS2 by Powell, Liang and Chadi.
Abstract: The energy band structure of 4H-SnS2 has been calculated using the local pseudopotential method in such a way that a direct comparison can be made with the band structure of 2H-SnS2 by Powell, Liang and Chadi (ibid., vol.11, p.885 (1978)). In particular, the two band structures are compared for the electron states in the vicinity of the band gap. The calculated band gap is found to be smaller in 4H-SnS2 than in 2H-SnS2, and this is in qualitative agreement with experiment.
16 citations