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

研究成果: Conference article同行評審

2 引文 斯高帕斯(Scopus)

摘要

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.

原文English
頁(從 - 到)631-635
頁數5
期刊Physica E: Low-Dimensional Systems and Nanostructures
21
發行號2-4
DOIs
出版狀態Published - 2004 三月
事件Proceedings of the Eleventh International Conference on Modulation (MSS11) - Nara, Japan
持續時間: 2003 七月 142003 七月 18

All Science Journal Classification (ASJC) codes

  • 電子、光磁材料
  • 原子與分子物理與光學
  • 凝聚態物理學

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