Conventional and microwave-modulated Shubnikov-de Haas oscillations in GaN electron systems

J. R. Juang, D. R. Hang, Tsai Yu Huang, W. K. Hung, Y. F. Chen, Gil Ho Kim, Ming Gu Lin, Tse Ming Chen, C. T. Liang, Y. Lee, Jae Hoon Lee, Jung Hee Lee

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Abstract

We report the drastic enhancement of Shubnikov-de Haas (SdH) oscillations observed in a GaN/AlGaN heterostructure by microwave modulation. The dependence of the SdH pattern on microwave power and temperature are investigated. The underlying mechanism is attributed to the effect of carrier heating. This technique has the advantage of keeping the carrier concentration fixed and not requiring expensive high-energy laser facilities compared with carrier-modulated SdH measurements. Moreover, we have investigated the low-temperature transport properties of front-gated Al0.18Ga 0.82N/GaN heterostructures. By changing the applied gate voltage, we can vary the carrier density in our sample. At high carrier densities (n > 4.65 × 1012 cm-2), the measured mobility (μ) is found to be a decreasing function of carrier density as μ∼n -0.31. Loss of mobility with increasing carrier density is dominated by interface roughness scattering. At low carrier densities (n < 4.24 × 1012 cm-2), the measured mobility is found to be an increasing function of carrier density as μ∼n0.34. This is consistent with remote ionized impurity scattering, although the measured exponent 0.34 is smaller than the typical value (0.7-1.5) observed in an AlGaN/GaN electron system. A possible reason is that our sample mobility is approximately five times lower than those in other devices for a similar electron density.

Original languageEnglish
Pages (from-to)631-635
Number of pages5
JournalPhysica E: Low-Dimensional Systems and Nanostructures
Volume21
Issue number2-4
DOIs
Publication statusPublished - 2004 Mar 1
EventProceedings of the Eleventh International Conference on Modulation (MSS11) - Nara, Japan
Duration: 2003 Jul 142003 Jul 18

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics

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    Juang, J. R., Hang, D. R., Huang, T. Y., Hung, W. K., Chen, Y. F., Kim, G. H., Lin, M. G., Chen, T. M., Liang, C. T., Lee, Y., Lee, J. H., & Lee, J. H. (2004). Conventional and microwave-modulated Shubnikov-de Haas oscillations in GaN electron systems. Physica E: Low-Dimensional Systems and Nanostructures, 21(2-4), 631-635. https://doi.org/10.1016/j.physe.2003.11.093