Oliver Ambacher

TL;DR: In this paper, the influence of the epitaxial layer roughness on the far-field profile of the optical mode in gallium nitride-based, c-plane ridge waveguide laser diodes was investigated.

Abstract: In this paper, a new large-signal model for gallium nitride high electron-mobility varactors is presented. Compared to former models, this model is scalable and describes the whole range of operation from breakdown to forward conduction. The model consists of a passive parasitic shell, an ideal intrinsic core, and takes dispersion into account. The main extraction is done on an eight-finger device with a tuning ratio of 4.3 and a minimum quality factor ${Q}$ above 30 for frequencies below 2 GHz. The model is verified for a large range of bias points and frequencies. Load–pull measurements provide evidence even at high RF input power up to 23 dBm.

TL;DR: In this article, the Debye and Drude models are used for the description of the frequency dependent admittance profiles in a range of depletion onset of the two-dimensional electron gas.

TL;DR: In this article, the authors investigated how integration of half-bridge transistors, drivers and freewheeling-diodes on a conductive Si-substrate influences DC-DC converter performance.

TL;DR: In this paper, the growth mechanisms along with the microstructural and optical properties of the MTPs aggregating a high density of "silicon-vacancy" complexes on the specific crystal irregularities are discussed.