Discrete surface state related to nitrogen-vacancy defect on plasma-treated GaN surfaces
Abstract
Detailed studies on the defect-related surface states of plasma-exposed n-GaN surfaces were carried out. An anomalous flat portion appeared in the metal-insulator-semiconductor capacitance-voltage characteristics for the sample exposed to H2 plasma, corresponding to a localized peak at EC-0.5 eV in the surface state density distribution. Atomic-force microscope and x-ray photoemission studies revealed the formation of Ga droplets on H2-plasma-treated GaN surfaces, caused by the desorption of nitrogen atoms in the form of NHx. These results suggested that a nitrogen-vacancy-related state near the conduction-band edge was introduced on the H2-plasma-treated GaN surface. No such effects took place on the N2-plasma-treated GaN surfaces.
- Publication:
-
Applied Physics Letters
- Pub Date:
- June 2002
- DOI:
- 10.1063/1.1485309
- Bibcode:
- 2002ApPhL..80.4564H
- Keywords:
-
- gallium compounds;
- III-V semiconductors;
- wide band gap semiconductors;
- ion-surface impact;
- surface structure;
- surface composition;
- defect states;
- atomic force microscopy;
- X-ray photoelectron spectra;
- vacancies (crystal);
- Atomic Force Microscopy;
- Beam Interactions;
- Broadband;
- Composition (Property);
- Crystal Defects;
- Defects;
- Gallium Compounds;
- Ion Impact;
- Nitrogen Plasma;
- Photoelectrons;
- Plasmas (Physics);
- Semiconductors (Materials);
- Surface Layers;
- Surface Treatment;
- Vacancies (Crystal Defects);
- X Ray Spectra;
- 73.20.Hb;
- 68.35.Dv;
- 81.65.-b;
- 79.20.Rf;
- 79.60.Bm;
- 73.20.At;
- 61.72.Ji;
- Solid-State Physics;
- Impurity and defect levels;
- energy states of adsorbed species;
- Composition segregation;
- defects and impurities;
- Surface treatments;
- Atomic molecular and ion beam impact and interactions with surfaces;
- Clean metal semiconductor and insulator surfaces;
- Surface states band structure electron density of states;
- Point defects and defect clusters