Demonstration of MOCVD-grown Ga2O3 power MOSFETs on sapphire with in-situ Si-doped by tetraethyl orthosilicate (TEOS).

In this work, we demonstrated Ga2O3-based power MOSFETs grown on c-plane sapphire substrates using in-situ TEOS doping for the first time. The ß-Ga2O3:Si epitaxial layers were formed by the metalorganic chemical vapor deposition (MOCVD) with a TEOS as a dopant source. The depletion-mode Ga2O3 power MOSFETs are fabricated and characterized, showing the increase of the current, transconductance, and breakdown voltage at 150 °C. In addition, the sample with the TEOS flow rate of 20 sccm exhibited a breakdown voltage of more than 400 V at RT and 150 °C, indicating that the in-situ Si doping by TEOS in MOCVD is a promising method for Ga2O3 power MOSFETs.

Cavity-sensitive amplified spontaneous emission with radiation reabsorption.

We experimentally and numerically investigate amplified spontaneous emission (ASE) in the presence of radiation reabsorption by using an end-pumped ruby laser. From the fluorescence time decay in the axial direction, we find that the average path length of ASE is much larger than the reabsorption length and exhibits sharp variation near the semi-concentric cavity configuration; however, the side lifetime is independent of cavity configuration. In addition, an axial power bump corresponding to a side power valley and the enhanced fluorescence R-line spectrum are observed and explained.