Time- and frequency-domain measurements of carrier lifetimes in GaN epilayers |
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Authors: | G Tamulaitis J Mickevi
ius P Vitta A
ukauskas MS Shur Q Fareed R Gaska |
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Institution: | aInstitute of Materials Science and Applied Research, Vilnius University, Saulėtekio 9-III, LT-10222 Vilnius, Lithuania;bDepartment of ECE and CIE, Rensselaer Polytechnic Institute, Troy, NY 12180, United States;cSensor Electronic Technology, Inc., 1195 Atlas Road, Columbia, SC 29209, United States |
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Abstract: | Results on time-resolved study of GaN photoluminescence (PL) in a power density range from 0.5 mW/cm2 under CW excitation by ultraviolet light emitting diode (UV LED) to 1 GW/cm2 under pulsed excitation by YAG:Nd laser in the temperature range from 8 to 300 K are presented. Measurements of PL response in the frequency domain by using amplitude-modulated emission of a UV LED as well as time-resolved PL measurements using a streak camera and light-induced transient grating technique have been used in the study. Yellow luminescence (YL) intensity increases with increasing temperature up to 120 K and faster components in YL decay switch to slower components with increasing temperature under UV LED excitation. At low carrier densities, the trapping decreases the carrier lifetime below 250 ps, while the carrier lifetime in the same GaN sample under excitation ensuring saturation of the traps equals 2 ns. |
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Keywords: | Gallium nitride Carrier lifetime Photoluminescence |
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