title: Determination of the electron-capture coefficients and the concentration of free electrons in GaN from time-resolved photoluminescence.
abstract: Point defects in high-purity GaN layers grown by hydride vapor phase epitaxy are studied by steady-state and time-resolved photoluminescence (PL). The electron-capture coefficients for defects responsible for the dominant defect-related PL bands in this material are found. The capture coefficients for all the defects, except for the green luminescence (GL1) band, are independent of temperature. The electron-capture coefficient for the GL1 band significantly changes with temperature because the GL1 band is caused by an internal transition in the related defect, involving an excited state acting as a giant trap for electrons. By using the determined electron-capture coefficients, the concentration of free electrons can be found at different temperatures by a contactless method. A new classification system is suggested for defect-related PL bands in undoped GaN.
authors.affiliation: Department of Physics, Virginia Commonwealth University, Richmond, VA 23284, USA.
authors.forename: M A
authors.initials: MA
authors.lastname: Reshchikov
authors.affiliation: Department of Physics, Virginia Commonwealth University, Richmond, VA 23284, USA.
authors.forename: J D
authors.initials: JD
authors.lastname: McNamara
authors.affiliation: Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA.
authors.forename: M
authors.initials: M
authors.lastname: Toporkov
authors.affiliation: Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA.
authors.forename: V
authors.initials: V
authors.lastname: Avrutin
authors.affiliation: Department of Physics, Virginia Commonwealth University, Richmond, VA 23284, USA.|Department of Electrical and Computer Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA.
authors.forename: H
authors.initials: H
authors.lastname: Morkoç
authors.affiliation: Nitride Crystals, Inc. 181E Industry Ct., Ste. B, Deer Park, NY 11729, USA.|Saint-Petersburg National Research University of Information Technologies, Mechanics and Optics, 49 Kronverkskiy Ave., 197101 Saint Petersburg, Russia.
authors.forename: A
authors.initials: A
authors.lastname: Usikov
authors.affiliation: Nitride Crystals, Inc. 181E Industry Ct., Ste. B, Deer Park, NY 11729, USA.
authors.forename: H
authors.initials: H
authors.lastname: Helava
authors.affiliation: Nitride Crystals, Inc. 181E Industry Ct., Ste. B, Deer Park, NY 11729, USA.
authors.forename: Yu
authors.initials: Y
authors.lastname: Makarov