The B3LYP hybrid density functional method, which is very successful in the study of thermochemistry of atoms and molecules, has been applied to some periodic systems recently. The applications to solids and surfaces show that the B3LYP hybrid functional reproduces the experimental energy gaps and magnetic moments for a variety of materials.
High-electron-mobility InN epilayers are achieved under the extremely In-rich condition on Si (111) substrates by molecular beam epitaxy. A directly probed electron mobility of 3640 cm2 V−1 s−1 and a residual electron concentration of 2.96 × 1017 cm−3 are detected by Hall-effect measurements at room temperature, which corresponds to a remarkable mobility of 3970 cm2 V−1 s−1 and an electron concentration of 2.45 × 1017 cm−3 in the InN bulk layer taking into account the electron accumulation layers with a density of 5.83 × 1013 cm−2 and a mobility of 429 cm2/V s. It is found that extremely the In-rich growth condition is most likely favorable to suppress impurity incorporation and weaken the dislocation scattering due to low proportionally charged dislocations, hence leading to high electron mobility.
Due to the intrinsic spontaneous and piezoelectric polarization effect, III‐nitride semiconductor heterostructures are promising candidates for generating 2D electron gas (2DEG) system. Among III‐nitrides, InN is predicted to be the best conductive‐channel material because its electrons have the smallest effective mass and it exhibits large band offsets at the heterointerface of GaN/InN or AlN/InN. Until now, that prediction has remained theoretical, due to a giant gap between the optimal growth windows of InN and GaN, and the difficult epitaxial growth of InN in general. The experimental realization of 2DEG at an InGaN/InN heterointerface grown by molecular beam epitaxy is reported here. The directly probed electron mobility and the sheet electron density of the InGaN/InN heterostructure are determined by Hall‐effect measurements at room temperature to be 2.29 × 103 cm2 V−1 s−1 and 2.14 × 1013 cm−2, respectively, including contribution from the InN bottom layer. The Shubnikov–de Haas results at 3 K confirm that the 2DEG has an electron density of 3.30 × 1012 cm−2 and a quantum mobility of 1.48 × 103 cm2 V−1 s−1. The experimental observations of 2DEG at the InGaN/InN heterointerface have paved the way for fabricating higher‐speed transistors based on an InN channel.
InGaN red light emitting diode (LED) is one of the crucial bottlenecks that must be broken through to realize high-resolution full-color mini/micro-LED displays. The efficiency of InGaN LEDs drops rapidly as the emission spectra go from blue/green to red range due to the poor quality of high-indium-content InGaN materials. Here, high-performance InGaN red LEDs on sapphire grown by metal-organic chemical vapor deposition through strain modulation are reported. A composite buffer layer is proposed to increase the surface lattice constant of GaN and hence successfully enhances the indium incorporation efficiency of the following InGaN active layers. Consequently, a highefficiency InGaN red mini-LED chip (mesa area: 100 × 200 µm 2 ) with a peak wavelength of 629 nm and an external quantum efficiency of 7.4% is realized. Finally, a full-color nitride mini-LED display panel with 74.1% coverage of Rec.2020 color gamut by using the InGaN red mini-LED chips is fabricated. The study signifies the great potentials of full-nitrides high-resolution fullcolor mini/micro-LED displays.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.