Determination of the surface potential of GaN:Si

Abstract

The surface potential of GaN:Si is determined for Si doping from 2.4 × 1017 cm–3 to 2.3 × 1019 cm–3 in layers grown by low pressure metal‐organic vapor‐phase epitaxy. We used the sheet resistance of the samples with different thicknesses measured by eddy current, a nondestructive, contactless method, to determine the depleted region. From the width of the depletion layer, which is dependent on the doping concentration, measured by secondary ion mass spectrometry, we obtained the GaN:Si surface potential on the basis of the depletion approximation. The surface potential decreases with increasing carrier concentration from about 1.6 eV down to 0.2 eV. Based on the behavior of the surface potential with doping we determined the surface state density. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Development of rugged 2 GHz power bars delivering more than 100 W and 60% power added efficiency

“…For the 3 nm cap sample we obtain Φ B =249 meV, while Φ B =171 meV and Φ B =585 meV are found for the other two samples with 1 nm and without cap, respectively. These results emphasize the findings presented in [9][10][11]…”

“…For the 3 nm cap sample we obtain Φ B =249 meV, while Φ B =171 meV and Φ B =585 meV are found for the other two samples with 1 nm and without cap, respectively. These results emphasize the findings presented in [9][10][11] and can be interpreted by a surface Fermi-level pinning close to the conduction band edge caused by a surface donor with high density of states. We observe a significant impact of the GaN cap layer thickness on the Schottky gate behaviour in forward and reverse directions, namely the ideality factor as well as the gate and drain leakage currents.…”

Regulating Schwann Cells Growth by Chitosan Micropatterning for Peripheral Nerve Regeneration In Vitro

“…It could be seen that the water contact angle of coverslips sample (CTL) was 24.88 AE 18, which was consistent with the value in the literature. [32] However, after being micropatterned with chitosan the water contact angle dramatically increased to 43.08 AE 1.88 and 55.68 AE 2.98, respectively. The results indicated that the chitosan micropatterning could increase the hydrophobicity of coverslips.…”

Avoidance of instable photoluminescence intensity from AlGaN bulk layers

“…Therefore, charge carrier recombination is subject to material characteristics at the AlGaN surface. The PL signal is influenced by the surface potential of approximately 1 eV and the surface field in the depletion layer as well as by surface recombination . Several studies for GaN already showed temporal changes in the luminescence intensity during PL measurements and pointed out that these changes are related to modifications at the semiconductor surface by the photo‐generated charge carriers in the presence of certain adsorbates .…”