Assignment of deep levels causing yellow luminescence in GaN
- 1 August 2004
- journal article
- Published by AIP Publishing in Journal of Applied Physics
- Vol. 96 (3), 1341-1347
- https://doi.org/10.1063/1.1757654
Abstract
The deep levels in GaN associated with yellow luminescence transitions have been investigated using photoluminescence, Hall measurements, and deep level transient spectroscopy(DLTS). Hall measurements on Si-doped GaN show the presence of donor levels at ∼18, ∼35, and ∼70 meV, which are respectively associated with the Si shallow donors, O impurities, and the nitrogen vacancies (V N ). DLTS measurements, on the other hand, reveal trap levels at E c −0.1 eV , E c −(0.2–0.24) eV , and E v +0.87 eV . The trap level at E c −0.1 eV obtained from DLTS can be correlated to the 70 meV deep donor (V N ) obtained from Hall measurements. The deep donor band at E c −(0.2–0.24) eV is attributed to the O N related defect complex decorated along dislocation sites while the hole level at E v +0.87 eV is attributed to the Ga vacancy (V Ga ). Thermal annealing at 750 °C in nitrogen ambient results in reduction of yellow luminescence, which could be due to decrease in the concentration of V N and O N -related defect complexes. From these observations, we propose that yellow luminescence in GaN arises from the transitions from the E c −(0.2–0.24) eV levels to the deep level at E v +0.87 eV .Keywords
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