Plasma-assisted molecular beam epitaxy of ZnO on in-situ grown GaN/4H-SiC buffer layers
Artikel i vetenskaplig tidskrift, 2015

Plasma-assisted molecular beam epitaxy (MBE) was used to grow ZnO (0001) layers on GaN(0001)/4H-SiC buffer layers deposited in the same growth chamber equipped with both N- and O-plasma sources. The GaN buffer layers were grown immediately before initiating the growth of ZnO. Using a substrate temperature of 440 degrees C-445 degrees C and an O-2 flow rate of 2.0-2.5 sccm, we obtained ZnO layers with smooth surfaces having a root-mean-square roughness of 0.3 nm and a peak-to-valley distance of 3 nm shown by AFM. The FWHM for X-ray rocking curves recorded across the ZnO(0002) and ZnO(10 (1) over bar5) reflections were 200 and 950 arcsec, respectively. These values showed that the mosaicity (tilt and twist) of the ZnO film was comparable to corresponding values of the underlying GaN buffer. It was found that a substrate temperature > 450 degrees C and a high Zn-flux always resulted in a rough ZnO surface morphology. Reciprocal space maps showed that the in-plane relaxation of the GaN and ZnO layers was 82.3% and 73.0%, respectively and the relaxation occurred abruptly during the growth. Room-temperature Hall-effect measurements showed that the layers were intrinsically n-type with an electron concentration of 10(19) cm(-3) and a Hall mobility of 50 cm(2).V-1.s(-1).

molecular beam epitaxy (MBE)

epitaxy

ZnO

Författare

David Adolph

Chalmers, Mikroteknologi och nanovetenskap (MC2), Fotonik

Tobias Tingberg

Chalmers, Mikroteknologi och nanovetenskap (MC2), Fotonik

Thorvald Andersson

Chalmers, Mikroteknologi och nanovetenskap (MC2), Mikrovågselektronik

Tommy Ive

Chalmers, Mikroteknologi och nanovetenskap (MC2), Fotonik

Frontiers of Materials Science

2095-025X (ISSN)

Vol. 9 2 185-191

Ämneskategorier

Materialteknik

Nanoteknik

DOI

10.1007/s11706-015-0292-x

Mer information

Skapat

2017-10-07