Influence of hydrostatic pressure on the built-in electric field in ZnO/ZnMgO quantum wells

Journal Article · Tue Jun 07 00:00:00 EDT 2016 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4953251· OSTI ID:22596770

Teisseyre, Henryk ^[1]; Kaminska, Agata; Suchocki, Andrzej; Kozanecki, Adrian ^[1]; Birner, Stefan ^[2]; Young, Toby D. ^[3]

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1. Institute of Physics, Polish Academy of Sciences, Al. Lotników 32/46, 02-668 Warsaw (Poland)
2. nextnano GmbH, Südmährenstr. 21, 85586 Poing (Germany)
3. Institute of Fundamental Technological Research, Polish Academy of Sciences, ul. Pawińskiego, 5b, 02-106 Warsaw (Poland)

We used high hydrostatic pressure to perform photoluminescence measurements on polar ZnO/ZnMgO quantum well structures. Our structure oriented along the c-direction (polar direction) was grown by plasma-assisted molecular beam epitaxy on a-plane sapphire. Due to the intrinsic electric field, which exists in polar wurtzite structure at ambient pressure, we observed a red shift of the emission related to the quantum-confined Stark effect. In the high hydrostatic pressure experiment, we observed a strong decrease of the quantum well pressure coefficients with increased thickness of the quantum wells. Generally, a narrower quantum well gave a higher pressure coefficient, closer to the band-gap pressure coefficient of bulk material 20 meV/GPa for ZnO, while for wider quantum wells it is much lower. We observed a pressure coefficient of 19.4 meV/GPa for a 1.5 nm quantum well, while for an 8 nm quantum well the pressure coefficient was equal to 8.9 meV/GPa only. This is explained by taking into account the pressure-induced increase of the strain in our structure. The strain was calculated taking in to account that in-plane strain is not equal (due to fact that we used a-plane sapphire as a substrate) and the potential distribution in the structure was calculated self-consistently. The pressure induced increase of the built-in electric field is the same for all thicknesses of quantum wells, but becomes more pronounced for thicker quantum wells due to the quantum confined Stark effect lowering the pressure coefficients.

• OSTI ID: 22596770
• Journal Information: Journal of Applied Physics, Vol. 119, Issue 21; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ELECTRIC FIELDS
MAGNESIUM OXIDES
MEV RANGE 10-100
MOLECULAR BEAM EPITAXY
MOLECULAR BEAMS
PHOTOLUMINESCENCE
PRESSURE COEFFICIENT
PRESSURE RANGE GIGA PA
QUANTUM WELLS
RED SHIFT
SAPPHIRE
STARK EFFECT
STRAINS
SUBSTRATES
THICKNESS
WELL PRESSURE
ZINC OXIDES