Single-particle relaxation times in a pseudomorphic In0.7Ga0.3 As/In0.52Al0.48As QW-HEMT structure with (4 1 1) A super-flat interfaces grown by MBE

✍ Scribed by Takahiro Kitada; Toyohiro Aoki; Issei Watanabe; Kenji Kanzaki; Satoshi Shimomura; Satoshi Hiyamizu

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 120 KB
• Volume: 13
• Category: Article
• ISSN: 1386-9477
• DOI: 10.1016/s1386-9477(02)00212-6

✦ Synopsis

Single-particle relaxation times in In0:7Ga0:3As=In 0:52 Al0:48As quantum well high electron mobility transistor (QW-HEMT) structures for two subbands (i = 0 and 1) are studied by fast Fourier transform analysis of Shubnikoov-de Haas (SdH) oscillations measured at 4 K in order to investigate remote impurity (RI) scattering in the QW-HEMT structure with e ectively atomically at interfaces over a wafer-size area ((4 1 1)A super-at interfaces) grown on a (4 1 1)A InP substrate by molecular beam epitaxy. The (4 1 1)A QW-HEMT structure with thin spacer thickness of 3 nm shows two times longer single-particle relaxation times ( s(0) = 0:71×10 -13 s and s(1) = 1:08×10 -13 s) compared to those ( s(0) = 0:37×10 -13 s and s(1) = 0:49×10 -13 s) for the corresponding QW-HEMT structure with conventional (1 0 0) interfaces, indicating that RI scattering is much reduced in the (4 1 1)A sample. Calculations of s(0) limited by RI scattering assuming random distribution of sheet-doped impurities show that the enhancement of s(0) for the (4 1 1)A QW-HEMT structure cannot be explained by laterally uniform spacer thickness resulting from the (4 1 1)A super-at interfaces. Much reduced RI scattering in the (4 1 1)A QW-HEMT structure is considered to be mainly caused by extremely uniform distribution of sheet-doped impurities.