Anomalous diffusion of Ga and As from semi-insulating GaAs substrate into MOCVD grown ZnO films as a function of annealing temperature and its effect on charge compensation
- Advanced Technology Development Centre, Indian Institute of Technology, Kharagpur 721 302 (India)
- School of Electrical Engineering and Computer Science, Oregon State University, 1148 Kelley Engineering Center, Corvallis, OR 97331–5501 (United States)
- UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452 001 (India)
The diffusion behavior of arsenic (As) and gallium (Ga) atoms from semi-insulating GaAs (SI-GaAs) into ZnO films upon post-growth annealing vis-à-vis the resulting charge compensation was investigated with the help of x-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy. The films, annealed at 600 ºC and 700 ºC showed p-type conductivity with a hole concentration of 1.1 × 10{sup 18} cm{sup −3} and 2.8 × 10{sup 19} cm{sup −3} respectively, whereas those annealed at 800 ºC showed n-type conductivity with a carrier concentration of 6.5 × 10{sup 16} cm{sup −3}. It is observed that at lower temperatures, large fraction of As atoms diffused from the SI-GaAs substrates into ZnO and formed acceptor related complex, (As{sub Zn}–2V{sub Zn}), by substituting Zn atoms (As{sub Zn}) and thereby creating two zinc vacancies (V{sub Zn}). Thus as-grown ZnO which was supposed to be n-type due to nonstoichiometric nature showed p-type behavior. On further increasing the annealing temperature to 800 ºC, Ga atoms diffused more than As atoms and substitute Zn atoms thereby forming shallow donor complex, Ga{sub Zn}. Electrons from donor levels then compensate the p-type carriers and the material reverts back to n-type. Thus the conversion of carrier type took place due to charge compensation between the donors and acceptors in ZnO and this compensation is the possible origin of anomalous conduction in wide band gap materials.
- OSTI ID:
- 22252875
- Journal Information:
- AIP Advances, Journal Name: AIP Advances Journal Issue: 5 Vol. 4; ISSN AAIDBI; ISSN 2158-3226
- Country of Publication:
- United States
- Language:
- English
Similar Records
Growth and conduction mechanism of As-doped p-type ZnO thin films deposited by MOCVD
Raman-scattering studies of silicon-implanted gallium arsenide: The role of amorphicity
Defect studies in low-temperature-grown GaAs
Journal Article
·
Fri Mar 15 00:00:00 EDT 2013
· Materials Research Bulletin
·
OSTI ID:22290401
Raman-scattering studies of silicon-implanted gallium arsenide: The role of amorphicity
Journal Article
·
Fri Mar 14 23:00:00 EST 1986
· J. Appl. Phys.; (United States)
·
OSTI ID:5955907
Defect studies in low-temperature-grown GaAs
Thesis/Dissertation
·
Sat Oct 31 23:00:00 EST 1992
·
OSTI ID:10140831