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Detection of interstitial Ga in GaN
1Department of Physics, Lehigh University, 16 Memorial Drive East, Bethlehem, Pennsylvania 18015, USA.
Physical Review Letters
|September 16, 2000
Summary
Researchers directly detected interstitial Gallium (Ga) in Gallium Nitride (GaN) using optical detection of electron paramagnetic resonance. This defect is stable until room temperature, where it migrates and forms new defects.
Area of Science:
- Materials Science
- Solid State Physics
- Semiconductor Physics
Background:
- Gallium Nitride (GaN) is a crucial semiconductor material.
- Understanding intrinsic defects in GaN is vital for device performance.
- Electron irradiation is a common method to introduce defects in semiconductors.
Purpose of the Study:
- To directly detect interstitial Gallium (Ga) in n-type GaN.
- To investigate the thermal stability and migration of interstitial Ga.
- To identify other mobile intrinsic defects in the GaN lattice.
Main Methods:
- In situ irradiation of n-type GaN with 2.5 MeV electrons at 4.2 K.
- Optical Detection of Electron Paramagnetic Resonance (ODEPR) to detect defects.
- Photoluminescence spectroscopy to monitor defect-induced changes.
Main Results:
- Direct detection of interstitial Ga in GaN via ODEPR.
- Interstitial Ga is stable until room temperature, then becomes mobile.
- A new defect emerges as interstitial Ga disappears, with a room temperature time constant of ~200 min.
- Another ODEPR center appears at ~135 K, indicating migration of other intrinsic defects.
Conclusions:
- Interstitial Ga is a mobile intrinsic defect in GaN.
- The migration and trapping of interstitial Ga lead to the formation of new, stable defects.
- GaN exhibits other mobile intrinsic defects that migrate at lower temperatures than interstitial Ga.