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Electron emission spectroscopy was performed on metalorganic chemical vapor deposition grown p-n−-n+ junctions with p-thicknesses ranging from 50 to 300 nm, doped with [Mg] = 3.5 × 1019 cm−3. By measuring the decreasing emitted electron intensity from a cesiated p-GaN surface with increasing p-thickness, we were able to extract the minority carrier diffusion length of electron in p-type GaN, Le = 26 ± 3 nm. The measured value is in good agreement with literature reported values. The extrapolated electron current at the n− region–p-GaN interface is in reasonable agreement with the simulated electron current at the interface.

Using electron emission spectroscopy, measurement and analysis were conducted on the energy distribution of vacuum emitted electrons from an electrically driven InGaN/GaN commercial blue c-plane (peak wavelengths λ≈465 nm) light emitting diode (LED) with 60 nm of p-GaN on top of the active region. The signal-to-noise ratio of semiconductor peaks is improved on the thin p-GaN LED compared to previously published data on thicker p-GaN samples and is attributed to reduced loss of electrons en route to emission into vacuum during transit through the p-GaN. This further proves that hot electrons are generated in the bulk region and not by light or other hot electron generation mechanisms at the surface. Using square root of the light output power as a proxy for the active region carrier density, n, the hot electron integrated peak intensity is shown to be proportional to n3 and, thus, is directly attributed to a 3-body Auger process. Since there are significant Auger recombination currents even at low injection current densities, it is expected that Auger recombination current will dominate over radiation recombination and Shockley–Read–Hall (SRH) currents at higher current densities. This identifies Auger recombination as the dominant cause of efficiency droop.

Vertical β-Ga2O3 Schottky diodes from metal-organic chemical vapor deposition (MOCVD)-grown epitaxial films are reported in this paper for high-power application devices. The Schottky diode, fabricated with a field termination structure, showed a low differential specific on-resistance of 0.67 mΩ cm2. Furthermore, the MOCVD-grown β-Ga2O3 vertical Schottky diodes exhibited a punch-through breakdown and a higher Baliga's figure-of-merit compared to those from other epitaxial growth methods of similar drift layer thickness. This suggests that the MOCVD growth, supporting high-quality epitaxy, can be promising for high-performance β-Ga2O3-based high-power devices.

The measurement of the energy distribution of vacuum emitted electrons from InGaN/GaN light-emitting diodes (LEDs) has proven essential in understanding the efficiency loss mechanism known as droop. We report on the measurement and identification of a new low-energy feature in addition to the previously measured three peaks present in the electron emission spectrum from a forward biased LED. Photoemission measurements show that the two low-energy peaks correspond to photoemitted electrons from each of the p-contact metals, palladium and gold. We confirm that the mid and high-energy peaks are due to electrons which have transited the p-type region of the device and have been emitted from the semiconductor surface from the bulk Γ-valley or a high-energy side valley.