Determination of surface barrier height and surface state density in GaN films grown on sapphire substrates

2004 ◽  
Vol 831 ◽  
Author(s):  
Seong-Eun Park ◽  
Joseph J. Kopanski ◽  
Youn-Seon Kang ◽  
Lawrence H. Robins ◽  
Hyun-Keel Shin
Keyword(s):  
Barrier Height ◽  
Surface State ◽  
Deep Level ◽  
Surface States ◽  
State Density ◽  
Beam Power ◽  
Surface Barrier ◽  
Surface State Density ◽  
Sapphire Substrates ◽  
Surface Electric Field

ABSTRACTPhotoreflectance (PR) modulation spectroscopy was performed to investigate surface properties of GaN films grown on sapphire substrates. From the period of the Franz-Keldysh oscillations, the surface electric field across the GaN space charge region was found to be (197 ± 11) kV/cm, which corresponds to a surface state density of 1.0×1012 cm−2. A surface barrier height of 0.71 eV was determined by fitting the dependence of the PR intensities on pump beam power density. We suggest that a deep level is formed at 2.68 eV above the GaN valence band edge due to the large density of surface states.

Studies of Surface State Densities of Semiconductors by Room-Temperature Photoreflectance

1999 ◽  
Vol 573 ◽  
Author(s):  
J. S. Hwan ◽  
G. S. Chang
Keyword(s):  
Fermi Level ◽  
Barrier Height ◽  
Surface State ◽  
Transport Theory ◽  
Thermionic Emission ◽  
State Density ◽  
Surface Barrier ◽  
Novel Approach ◽  
State Densities ◽  
Surface Fermi Level

ABSTRACTIn this study, we develop a novel approach to determine the surface Fermi level and the surface state densities of semiconductors. The built-in electric field and thus the surface barrier height are evaluated from the Franz-Keldysh oscillations in the PR spectra. Based on the thermionic-emission theory and current-transport theory, the surface state density as well as the pinning position of the surface Fermi level can be determined from the dependence of the surface barrier height on the pump beam intensity. Even though this method is significantly simpler, easier to perform, and time efficient compared with other approaches, the results obtained agree with the literature.

In-Situ Characterization of the Surface State Density by Photoluminescence During Electrochemical Treatments of Silicon Surfaces

1996 ◽  
Vol 451 ◽  
Author(s):  
T. Dittrich ◽  
V. Y. Timoshenko ◽  
J. Rappich
Keyword(s):  
Anodic Oxidation ◽  
Surface State ◽  
Surface States ◽  
State Density ◽  
Silicon Surfaces ◽  
In Situ Characterization ◽  
Surface State Density ◽  
Pl Intensity

ABSTRACTThe photoluminescence (PL) of c-Si is probed stroboscopically with single pulses of a N2 laser during electrochemical treatments (hydrogenation and anodic oxidation). The PL intensity of indirect semiconductors such as Si is controlled by the non-radiative surface and bulk recombination. By this reason the density of surface states can be estimated for unknown surfaces by using a calibrated standard. The surface state density of a hydrogenated Si surface increases by exchanging the electrolyte by gaseous N2 or water.

Surface state density decrease in nanostructured polycrystalline SnO2: modelling and experimental evidence

2004 ◽  
Vol 100 (1-2) ◽  
pp. 283-286 ◽  
Author(s):  
C. Malagù ◽  
M.C. Carotta ◽  
H. Fissan ◽  
V. Guidi ◽  
M.K. Kennedy ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Surface State ◽  
State Density ◽  
Surface State Density ◽  
Density Decrease

Correlation between Photoluminescence and Surface-State Density on GaAs Surfaces Subjected to Various Surface Treatments

1988 ◽  
Vol 27 (Part 2, No. 11) ◽  
pp. L2177-L2179 ◽  
Author(s):  
Hideki Hasegawa ◽  
Toshiya Saitoh ◽  
Seiichi Konishi ◽  
Hirotatsu Ishii ◽  
Hideo Ohno
Keyword(s):  
Surface State ◽  
State Density ◽  
Surface Treatments ◽  
Surface State Density
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