Low interfacial density of states around midgap in MBE-Ga2O3(Gd2O3)/In0.2Ga0.8As

✍ Scribed by C.A. Lin; H.C. Chiu; T.H. Chiang; Y.C. Chang; T.D. Lin; J. Kwo; W.-E. Wang; J. Dekoster; M. Heyns; M. Hong

• Publisher: Elsevier Science
• Year: 2011
• Tongue: English
• Weight: 693 KB
• Volume: 323
• Category: Article
• ISSN: 0022-0248
• DOI: 10.1016/j.jcrysgro.2011.01.108

✦ Synopsis

Systematic temperature-dependent capacitance-voltage and conductance measurements were used to study the electrical characteristics of molecular beam epitaxy (MBE) and atomic layer deposition (ALD) oxides on In 0.2 Ga 0.8 As/GaAs. The distribution of interfacial density of states (D it ) within the band gap of In 0.2 Ga 0.8 As was deduced with the conductance method. The MBE-grown Ga 2 O 3 (Gd 2 O 3 )/In 0.2 Ga 0.8 As, with an excellent tailored interface, has given D it values of $ 5 Â 10 11 eV À 1 cm À 2 above, $ 2 Â 10 12 eV À 1 cm À 2 below, and 1-7 Â 10 12 eV À 1 cm À 2 around the mid-gap region (0.5-0.7 eV above valence band maximum (E V )); the high D it value near the mid-gap, extracted at 100 and 150 1C, may be related to the temperature effect, which tends to induce more trap excitations. In contrast, the ALD-Al 2 O 3 /In 0.2 Ga 0.8 As has yielded higher D it values of410 13 eV À 1 cm À 2 around the mid-gap region.