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: The (111) double layer with the maximum number of Ge-Ge bonds is found to be energetically the most stable and to have the smallest dipole, but it is still large compared to typical band offsets in semiconductors.
Abstract: We have carried out ab initio self-consistent calculations to investigate the extent to which the band offset can be modified by polar layers. The cases studied are double layers of Ge in bulk GaAs (for which the offsets are totally due to induced dipoles) in (100) and two distinctly different (111) geometries. The (111) double layer with the maximum number of Ge-Ge bonds is found to be energetically the most stable and to have the smallest dipole, but it is still large (0.7 eV) compared to typical band offsets in semiconductors. We argue that this demonstrates the potential possibility of providing a mechanism for band-offset engineering using thin layers at interfaces.
75 citations
TL;DR: In this paper, the electrical and optical properties of isotype p-P organic heterojunctions (HJ) consisting of CuPc (copper phthalocyanine) and PTCDA (3,4,9,10 perylenetetracarboxylic dianhydride) were studied.
Abstract: We have studied the electrical and optical characteristics of isotype p‐P organic heterojunctions (HJ) consisting of CuPc (copper phthalocyanine) and PTCDA (3,4,9,10‐perylenetetracarboxylic dianhydride). It is found that the charge‐transport properties of the heterojunction are limited by thermionic emission of holes over the energy barrier at the CuPc/PTCDA heterojunction at low forward and reverse bias, and by series resistance at high voltage. The heterojunction energy barrier at the CuPc/PTCDA valence‐band edge was measured using both current‐voltage and capacitance‐voltage analysis and was found to be ΔEvC,P=0.48±0.05 eV. Similar measurements made for HJs consisting of CuPc and PTCDA in combination with another perylene‐based material, 3, 4, 9, 10‐perylenetetracarboxylic‐bis‐benzimidazole (PTCBI), suggest that the band offsets for these three materials follow a transitive relationship. That is, ΔEvC,P=ΔEvC,B−ΔEvB,P, where subscripts C, P, and B refer to CuPc, PTCDA, and PTCBI, respectively. The resul...
75 citations
TL;DR: In this paper, the authors reexamine a well-established method for determining valence band maxima (VBM) in semiconductors based on fitting photoemission valence bands spectra to theoretical densities of states.
74 citations
TL;DR: In this paper, the electronic, optical, and photocatalytic properties of GaSe/HfS2 heterostructures are studied via first-principles calculations.
74 citations
TL;DR: In this paper, a GeSe/SnSe heterostructure has type-II band alignment and a direct band gap, which can effectively prevent the recombination of photogenerated electron-hole pairs.
Abstract: Based on the first-principles calculations, we demonstrated that a GeSe/SnSe heterostructure has type-II band alignment and a direct band gap, which can effectively prevent the recombination of photogenerated electron–hole pairs. Moreover, the GeSe/SnSe heterostructure also exhibits strong optical absorption intensity, which can reach the order of 105 cm−1. Our predicted photoelectric conversion efficiency (PCE) for the GeSe/SnSe heterostructure reaches 21.47%. We also found that the hole carrier mobility of the GeSe/SnSe heterostructure along the x direction has been significantly improved to 6.42 × 104 cm2 V−1 s−1, which is higher than that of black phosphorus (1 × 104 cm2 V−1 s−1). By applying a vertical external electric field, we found that the band gap and band offset of the GeSe/SnSe heterojunction can be effectively tuned. The revealed type-II band alignment, strong optical absorption, superior PCE and superior hole carrier mobility of the GeSe/SnSe heterostructure imply that this new proposed material has broad application prospects in solar cells.
74 citations