Modeling and simulation of AlGaN/InGaN/GaN double heterostructures using distributed surface donor states

2018 ◽  
Vol 57 (8) ◽  
pp. 080305 ◽  
Author(s):  
Joydeep Ghosh ◽  
Swaroop Ganguly
Keyword(s):  
Modeling And Simulation ◽  
Double Heterostructures ◽  
Donor States ◽  
Surface Donor

STM studies of Fermi-level pinning on the GaAs(001) surface

1993 ◽  
Vol 344 (1673) ◽  
pp. 533-543 ◽  
Keyword(s):  
Fermi Level ◽  
Valence Band ◽  
Surface Defects ◽  
Defect Density ◽  
Valence Band Maximum ◽  
Intrinsic Defect ◽  
Fermi Level Pinning ◽  
Donor States ◽  
P Type ◽  
Surface Donor

This paper reviews recent scanning tunnelling microsopy (STM) studies of Fermi-level pinning on the surface of both n- and p-type GaAs(001). The samples are all grown by molecular beam epitaxy and have a (2 x 4)/c(2 x 8) surface reconstruction. The STM has shown that on the surface of highly doped n-type GaAs(001) there is a high density of kinks in the dimer-vacancy rows of the (2 x 4) reconstruction. These kinks are found to be surface acceptors with approximately one electron per kink. The kinks form in exactly the required number to pin the Fermi-level of n-type GaAs(001) at an acceptor level close to mid gap, irrespective of doping level. The Fermi-level position is confirmed with tunnelling spectroscopy. No similar surface donor states are found on p-type GaAs(001). In this case Fermi-level pinning results from ‘intrinsic’ surface defects such as step edges. Since this intrinsic defect density is independent of doping, at high doping levels the Fermi-level on p-type GaAs(001) moves down in the band gap towards the valence band. Tunnelling spectroscopy on p-type GaAs(001) doped 10 19 cm -3 with Be shows the Fermi-level to be 150 mV above the valence band maximum

scholarly journals Identification of Buffer and Surface Traps in Fe-Doped AlGaN/GaN HEMTs Using Y21 Frequency Dispersion Properties

Electronics ◽  
2021 ◽  
Vol 10 (24) ◽  
pp. 3096
Author(s):  
P. Vigneshwara Raja ◽  
Nandha Kumar Subramani ◽  
Florent Gaillard ◽  
Mohamed Bouslama ◽  
Raphaël Sommet ◽  
...  
Keyword(s):  
Low Frequency ◽  
Frequency Dispersion ◽  
Drain Current ◽  
Surface Region ◽  
Electron Trap ◽  
High Electron ◽  
Trap States ◽  
Dispersion Properties ◽  
Donor States ◽  
Surface Donor

The buffer and surface trapping effects on low-frequency (LF) Y-parameters of Fe-doped AlGaN/GaN high-electron mobility transistors (HEMTs) are analyzed through experimental and simulation studies. The drain current transient (DCT) characterization is also carried out to complement the trapping investigation. The Y22 and DCT measurements reveal the presence of an electron trap at 0.45–0.5 eV in the HEMT structure. On the other hand, two electron trap states at 0.2 eV and 0.45 eV are identified from the LF Y21 dispersion properties of the same device. The Y-parameter simulations are performed in Sentaurus TCAD in order to detect the spatial location of the traps. As an effective approach, physics-based TCAD models are calibrated by matching the simulated I-V with the measured DC data. The effect of surface donor energy level and trap density on the two-dimensional electron gas (2DEG) density is examined. The validated Y21 simulation results indicate the existence of both acceptor-like traps at EC –0.45 eV in the GaN buffer and surface donor states at EC –0.2 eV in the GaN/nitride interface. Thus, it is shown that LF Y21 characteristics could help in differentiating the defects present in the buffer and surface region, while the DCT and Y22 are mostly sensitive to the buffer traps.

Interaction of Oxygen with Native Chemical Defects in CuInSe2 Thin Films

1989 ◽  
Vol 148 ◽  
Author(s):  
Rommel Noufi ◽  
David Cahen
Keyword(s):  
Thin Films ◽  
Chemical Model ◽  
Near Surface ◽  
Polycrystalline Thin Films ◽  
Donor States ◽  
Surface Donor

ABSTRACTWe formulate a consistent defect chemical model of the effect of air/02 anneals on CuInSe2 polycrystalline thin films. The model centers on O-induced neutralization of (near) surface donor states in CuInSe2 grains. The simplest identification of these states is with ionized Se vacancies, due to coordinatively unsaturated In on grain surfaces and boundaries.

Sign in / Sign up

Export Citation Format

Share Document