High electron mobility of epitaxial ZnO thin films on c-plane sapphire grown by multistep pulsed-laser deposition

被引：571

作者：

Kaidashev, EM ^{[1
]}

Lorenz, M ^{[1
]}

von Wenckstern, H ^{[1
]}

Rahm, A ^{[1
]}

Semmelhack, HC ^{[1
]}

Han, KH ^{[1
]}

Benndorf, G ^{[1
]}

Bundesmann, C ^{[1
]}

Hochmuth, H ^{[1
]}

Grundmann, M ^{[1
]}

机构：

[1] Univ Leipzig, Fak Phys & Geowissensch, Inst Expt Phys 2, D-04103 Leipzig, Germany

来源：

APPLIED PHYSICS LETTERS | 2003年 / 82卷 / 22期

关键词：

D O I：

10.1063/1.1578694

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

A multistep pulsed-laser deposition (PLD) process is presented for epitaxial, nominally undoped ZnO thin films of total thickness of 1 to 2 mum on c-plane sapphire substrates. We obtain reproducibly high electron mobilities from 115 up to 155 cm(2)/ Vs at 300 K in a narrow carrier concentration range from 2 to 5 x 10(16) cm(-3). The key issue of the multistep PLD process is the insertion of 30-nm-thin ZnO relaxation layers deposited at reduced substrate temperature. The high-mobility samples show atomically flat surface structure with grain size of about 0.5-1 mum, whereas the surfaces of low-mobility films consist of clearly resolved hexagonally faceted columnar grains of only 200-nm size, as shown by atomic force microscopy. Structurally optimized PLD ZnO thin films show narrow high-resolution x-ray diffraction peak widths of the ZnO(0002) omega- and 2Theta-scans as low as 151 and 43 arcsec, respectively, and narrow photoluminescence linewidths of donor-bound excitons of 1.7 meV at 2 K. (C) 2003 American Institute of Physics.

引用

页码：3901 / 3903

页数：3