β-Ga2O3 epitaxial thin films were deposited using laser molecular beam epitaxy technique and oxygen atmosphere in situ annealed in order to reduce the oxygen vacancy. Metal/semiconductor/metal structured photodetectors were fabricated using as-grown film and annealed film separately. Au/Ti electrodes were Ohmic contact with the as-grown films and Schottky contact with the annealed films. In compare with the Ohmic-type photodetector, the Schottky-type photodetector takes on lower dark current, higher photoresponse, and shorter switching time, which benefit from Schottky barrier controlling electron transport and the quantity of photogenerated carriers trapped by oxygen vacancy significant decreasing.
Current crowding in mesa-structure GaInN/GaN light emitting diodes (LEDs) grown on insulating substrates is analyzed. A model developed reveals an exponential decrease of the current density with distance from the mesa edge. Devices with stripe-shaped mesa geometry display current crowding and a saturation of the optical output power at high injection currents. It is shown that the optical power saturation depends on the device geometry. It is also shown that saturation is less pronounced in LEDs employing a ring-shaped mesa geometry, which reduces current crowding, as compared to the conventional square-shaped mesa geometry.
GaN/InGaN light-emitting diodes (LEDs) with different mesa structures are studied. The optical emission power as well as current–voltage characteristics of different mesa patterns are measured. The results show that the optical emission of the device with interdigitated patterns is higher than devices with traditional square-shaped patterns. The leakage current is found to increase as the mesa sidewall perimeter increases. Based on the analysis, it is concluded that a surface leakage current flows across the mesa sidewall and the leakage current is directly proportional to the mesa perimeter. The implications of the results for large-area scalable LED structures are discussed.
In order to resolve the problems existing in the conventional phosphor-converted light-emitting-diodes (LEDs) and red-green-blue LEDs, the cascade single-chip phosphor-free white LED was proposed with GaAs∕GaN heterojunction direct wafer bonding. Corresponding to the color-matching calculation, the white LED demonstrated the CIE chromaticity coordinates of about (0.3, 0.3) at 20mA, which was very close to the ideal white light position (1∕3, 1∕3) on the chromaticity diagram. The fabrication and the electrical and optical performances of such white LEDs were described.
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.