High spatial resolution thermal conductivity and Raman spectroscopy investigation of hydride vapor phase epitaxy grown n-GaN/sapphire (0001): Doping dependence
| Autor: | D. I. Florescu, Fred H. Pollak, Richard J. Molnar, C. E. C. Wood, V. M. Asnin |
|---|---|
| Rok vydání: | 2000 |
| Předmět: | |
| Zdroj: | Journal of Applied Physics. 88:3295-3300 |
| ISSN: | 1089-7550 0021-8979 |
| DOI: | 10.1063/1.1289072 |
| Popis: | We have measured high resolution thermal conductivity (κ) and Raman spectra {E2 mode [high frequency], A1 mode [longitudinal optical (LO)], and high frequency LO-plasmon coupled mode [LPP+]} at 300 K of three series of n-GaN/sapphire (0001) samples fabricated by hydride vapor phase epitaxy (HVPE). The former was determined with a scanning thermal microscope while the latter was obtained using a micro-Raman system, both having a spatial resolution of ≈2–3 μm. For all three sets of samples the thermal conductivity decreased linearly with log n, about a factor of two decrease in κ for every decade increase in n. Also, we found a correlation between film thickness and improved thermal conductivity. Furthermore, κ≈1.95 W/cm K for one of the most lightly doped samples (≈6.9×1016 cm−3), higher than previously reported κ≈1.7–1.8 W/cm K on lateral epitaxial overgrown (LEO) material with n≈(1–2)×1017 cm−3 [V. M. Asnin et al., Appl. Phys. Lett. 75, 1240 (1999)], κ=1.55 W/cm K on LEO samples using a third-harmonic te... |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|