Optical properties of GaN/AlGaN QW nanostructures with different well and barrier widths
2007 (English)In: Journal of Physics: Condensed Matter, ISSN 0953-8984, Vol. 19, no 35Article in journal (Refereed) Published
Optical properties of wurtzite AlGaN/GaN quantum well (QW) structures grown by molecular-beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD) on c-plane sapphire substrates have been investigated by means of photoluminescence (PL) and time-resolved photoluminescence (TRPL) at low temperature. The PL spectra exhibit a blue-shifted emission of GaN/AlGaN QW nanostructures by decreasing the barrier width, in contrast to the arsenide system (Pabla A S et al 1993 Appl. Phys. Lett. 63 752). This behavior is attributed to a redistribution across the samples of the huge built-in electric field (several hundreds of kV cm(-1)) induced by the polarization difference between wells and barriers. The trend of the barrier width dependence of the internal polarization field is reproduced by using simple electrostatic arguments. In addition, the effect of well width variation on the optical transition and decay time of GaN multiple quantum wells (MQWs) have been investigated, and it has been shown that the screening of the piezoelectric field and the electron-hole separation are strongly dependent on the well thickness and have a profound effect on the optical properties of the GaN/AlGaN MQWs. The time-resolved PL spectra of 3 nm well MQWs reveal that the spectral peak position shifts toward lower energies as the decay time increases and becomes red-shifted at longer decay times.
Place, publisher, year, edition, pages
2007. Vol. 19, no 35
National CategoryEngineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-45913DOI: 10.1088/0953-8984/19/35/356218OAI: oai:DiVA.org:liu-45913DiVA: diva2:266809