Evaluation of interfacial structure of [111] and [001] oriented epitaxial NiO layers on GaAs substrate by non-destructive techniques

• Published in: Vacuum Vol. 159; pp. 335 - 340
• Main Authors: Singh, S.D., Das, Arijeet, Swami, M.K., Goutam, U.K., Sharma, R.K., Patel, H.S., Rai, S.K., Ganguli, Tapas
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-01-2019
• Subjects: Epitaxy; Interface; Raman; Wide band gap semiconductors; XRD; Raman; XRD; Wide band gap semiconductors; Epitaxy; Interface
• ISSN: 0042-207X; 1879-2715
• DOI: 10.1016/j.vacuum.2018.10.030

The interface at NiO and GaAs heterojunction is found to have claudetite phase of As2O3 with monoclinic structure, which increases with oxygen (O2) partial pressure. It is determined that rough interface, caused by recrystallization of GaAs surface along [111] direction, is not the main governing factor for the observed change in growth direction for NiO epitaxial layer from [111] to [001] direction with increase in O2 partial pressure. The out-of-plane and in-plane epitaxial relationships of [111] oriented NiO layer with respect to substrate are [111]NiO || [001]GaAs, [-1-12]NiO || [-1-10]GaAs and [-110]NiO || [-110]GaAs. The interfacial structure of NiO/GaAs heterojunction thus determined can have implications into the characteristics of optoelectronic devices based on this heterojunction.
•Change in growth orientation from [111] to [001] for NiO layer grown on [001]GaAs substrates with O2 pressure.•Rough interface is not found to be the main governing factor for observed change in growth direction.•Oxidation ambient strength present during growth is responsible for change of growth direction.•Interface at NiO/GaAs heterojunction is found to have claudetite phase of As2O3 with monoclinic structure.•Out-of-plane epitaxial relationship of [111] NiO layer with substrate is [111]NiO || [001]GaAs.•In-plane epitaxial relationships of [111] NiO layer with substrate are [-1-12]NiO || [-1-10]GaAs and [-110]NiO || [-110]GaAs.