Deep States in GaN Studied by Thermally Stimulated Current Spectroscopy

1995 ◽  
Vol 395 ◽  
Author(s):  
Z.C. Huang ◽  
J.C. Chen ◽  
D.B. Mott
Keyword(s):  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Surface States ◽  
Chemical Vapor ◽  
Deep Levels ◽  
Band Edge ◽  
Conduction Band Edge ◽  
Thermally Stimulated Current ◽  
Furnace Annealing ◽  
Thermally Stimulated Current Spectroscopy

ABSTRACTDeep levels in insulating GaN grown by metalorganic chemical vapor deposition have been studied using thermally stimulated current (TSC) and photocurrent (PC) spectroscopies. Five main traps were observed by TSC measurement in the as-grown undoped GaN in the range of 0-0.75 eV below the conduction band edge or above the valence band edge. Their activation energies were 0.11, 0.24, 0.36, 0.53 and 0.62 eV, respectively. PC measurements showed three deep levels located within the bandgap at 1.32, 1.70 and 2.36 eV, respectively. Furnace annealing was carried out on GaN for identifying all the observed deep levels. We have found that the 0.24, 0.36 and 0.53 eV traps were eliminated by annealing at 1000°C under N2for six hours, whereas the 0.62 eV trap density increased after annealing. The three deep levels detected by the PC measurement were not affected by annealing. The 1.70 eV trap, which is located at the midgap, does not seem to compensate with narrow donors. We attribute the 0.11 eV trap to surface states, and the 0.62 eV trap to nitrogen vacancies.

Very Low Deep Level AlxGa1−xAs (x=0.22) Layer Grown by Metalorganic Chemical Vapor Deposition

1995 ◽  
Vol 378 ◽  
Author(s):  
Z. C. Huang ◽  
Bing Yang ◽  
H. K. Chen ◽  
J. C. Chen
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Deep Level ◽  
Chemical Vapor ◽  
Deep Levels ◽  
Se Doping ◽  
Transient Spectroscopy ◽  
Low Selenium ◽  
Metalorganic Chemical

ABSTRACTWe have achieved deep-level-free Al0.22Ga0.78As epitaxial layers using low selenium (Se)-doping (8.4 × l016 cm−3) grown by metalorganic chemical vapor deposition (MOCVD). Deep levels in various Al0.22Ga0.78As layers grown on GaAs substrates were measured by deep level transient spectroscopy (DLTS). We have found that the commonly observed oxygen contamination-related deep levels at EC-0.53 and 0.70 eV and germanium-related level at EC-0.30 eV in MOCVD-grown Al0.22Ga0.78 As can be eliminated by low Se-doping. In addition, a deep hole level located at Ev+0.65 eV was found for the first time in highly Se-doped Al0.22Ga0.78 As epilayers. We suggest that low Se-doping (<2 × 1017 cm−3) produces a passivation effect and then deactivates other deep levels in Al0.22Ga0.78As.

Low Deep Impurity InxGa1-xP Grown by Metalorganic Chemical Vapor Deposition

1995 ◽  
Vol 378 ◽  
Author(s):  
Z. C. Huang ◽  
Bing Yang ◽  
H. K. Chen ◽  
J. C. Chen
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Lattice Mismatch ◽  
Deep Level ◽  
Chemical Vapor ◽  
Deep Levels ◽  
Electron Trap ◽  
Deep Impurity ◽  
Metalorganic Chemical

AbstractInxGai-xP (x=0.49) layers lattice-matched to GaAs have been grown by metalorganic chemical vapor deposition (MOCVD). We did not observe any deep levels in the temperature range of 30-380K by deep level transient spectroscopy (DLTS) in undoped In0.49Ga0.51P layers which have a background concentration of 3.1×1015 cm−3. The deep levels, if they exist, have a concentration of less than 5×1011 cm−3, which is the lowest deep level concentration found so far in InxGa1-xP materials. Moreover, lattice-mismatched InxGa1-xP/GaAs heterojunctions were deliberately grown by varying the In-composition ranging from 0.43 to 0.57. No deep levels were created in 1-μm-thick InxGa1-xP layers due to lattice mismatch when 0.469 < x < 0.532. However, we have observed a shallow electron trap at EC - 60 meV in InxGa1-xP layers with x < 469, and a deep electron trap located at Ec - 0.85 eV in the samples with x > 0.532. We suggest that the lattice-mismatch-induced-defects in InxGa1-xP are either electrically inactive or resided outside the bandgap when In content ranging from 0.469 to 0.532.

Silicon cross doping and its effect on the Si or Be implantation doping of gallium arsenide grown on (100) silicon by metalorganic chemical vapor deposition

1992 ◽  
Vol 7 (8) ◽  
pp. 2186-2193 ◽  
Author(s):  
B. Molnar ◽  
P. Chi ◽  
D. Simons
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Chemical Vapor ◽  
Gaas Layer ◽  
Furnace Annealing ◽  
Si Substrates ◽  
Local Vibrational Mode ◽  
Metalorganic Chemical

A study of the cross doping of GaAs layers grown by a two-step metalorganic chemical vapor deposition on Si substrates is reported. All as-grown, unintentionally doped layers of GaAs were n-type, and the carrier profiles tracked the Si atomic profiles. Furnace annealing at 850 °C for 30 min in an arsine overpressure, which is used to improve the crystalline quality of the GaAs near the heterointerface, caused additional Si to diffuse into the GaAs layer. Comparison of the Si concentration at the interface with the carrier concentration suggested the presence of compensating acceptors. Resonance Raman scattering by the SiAs local vibrational mode near the interface shows that a fraction of the Si atoms are localized at the As sites. The furnace annealing increased the Si concentration in the 1.7–1.8 μm thick initially grown GaAs layer. This, in turn, influenced the electrical profiles created with Si or Be implantation on a 2.3 μm thick GaAs layer.

Nitride-Rich Hexagonal GaNP Growth Using Metalorganic Chemical Vapor Deposition

2000 ◽  
Vol 639 ◽  
Author(s):  
Seikoh Yoshida ◽  
Yoshiteru Itoh ◽  
Junjiroh Kikawa
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Light Emitting Diode ◽  
Chemical Vapor ◽  
Band Edge ◽  
Band Edge Emission ◽  
Edge Emission ◽  
Different Temperatures ◽  
Metalorganic Chemical

ABSTRACTThe growth of GaNP using laser-assisted metalorganic chemical vapor deposition (LA-MOCVD) was carried out for the fabrication of a light-emitting diode (LED). We used an Ar-F laser in order to decompose the source gases at lower temperatures. Trimethylgallium (TMG), ammonia (NH3) and tertialybuthylphosphine (TBP) were used for the growth. GaNP growth was carried out at different temperatures. After that, annealing was carried out at 1273-1373 K to improve the crystal quality.As a result, N-rich GaNP could be grown at 1123-1223 K. The surface morphologies of GaNP were improved when the growth temperature was increased to above 1173 K. We investigated the photoluminescence (PL) of GaNP. The band-edge emission of GaNP was observed at 77 K upon applying thermal annealing at 1323 K. This peak shifted to about 0.2 eV compared with the GaN band-edge emission. Furthermore, a GaNP LED was fabricated and the electoluminescence spectra were investigated. The band-edge emission at 420 nm was observed.

Studies of Electrically and Recombination Active Centers in Undoped GaN Grown by OMVPE

1996 ◽  
Vol 449 ◽  
Author(s):  
A. Y. Polyakov ◽  
A. V. Govorkov ◽  
N. B. Smirnov ◽  
M. Shin ◽  
M. Skowronski ◽  
...  
Keyword(s):  
Band Edge ◽  
Conduction Band Edge ◽  
Thermally Stimulated Current ◽  
Active Centers ◽  
Spatially Resolved ◽  
Thermally Stimulated Current Spectroscopy ◽  
Electron Beam Induced Current ◽  
Recombination Centers ◽  
Transient Spectroscopy ◽  
Dislocation Walls

ABSTRACTDeep centers were studied in GaN samples grown by organometallic vapor phase epitaxy (OMVPE). Electron traps 0.2 eV and 0.5 eV below conduction band edge and 0.25 eV and 0.50.85 eV above the valence band edge were detected by means of deep levels transient spectroscopy (DLTS), photoelectron relaxation spectroscopy (PERS) and thermally stimulated current spectroscopy (TSC). The photoconductivity at low temperature is shown to be persistent and the magnitude of photosensitivity is dependent on the way the samples are grown. Microcathodoluminescence (MCL) and electron beam induced current (EBIC) measurements indicate that the density of deep recombination centers near the dislocation walls between the misoriented GaN domains is lower than inside the domains. Spatially resolved PERS measurements show that the concentration of the 0.85 eV level is higher in the low angle grain boundary regions that produce bright contrast in EBIC and MCL.

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