Programme

P.8 -- Poster

Date: Friday, 24 November 2017

Time: 10:30 - 11:20

Tunneling at room temperature in GaAs/AlGaAs asymmetric coupled double quantum wells observed via time-resolved photoluminescence spectroscopy

R. B. Jaculbia, J.P. Afalla, M. H. Balgos, K. Omambac, D. A. Lumantas*, A. Salvador, E. Estacio, and A. Somintac

National Institute of Physics, University of the Philippines, Diliman, Quezon City, Philippines, 1101

We report an experimental evidence of non-resonant phonon assisted tunneling at room temperature in in GaAs/AlGaAs asymmetric coupled double quantum wells (ACDQW's) using time resolved photoluminescence (TRPL) spectroscopy at 300 K. Two ACDQW samples (A and B) with a barrier thickness of 25 Å were grown via molecular beam epitaxy. A double quantum well with a barrier thickness of 100 Å was used as a reference sample. The energy separation (ΔE) between the ground state of the conduction band of the wide well and that of the narrow well are 42.7 meV and 19.5 meV, for samples A and B respectively. The TRPL measurement revealed a double decay rate in sample A whose ΔE is greater than one GaAs LO phonon energy (36 meV), suggesting a phonon assisted tunneling mechanism. Power-dependent TRPL measurement showed a decrease in the decay time of the TRPL spectra of the wide well of sample A with increasing pump power. This is opposite to the observed behavior in the reference sample. The evidence of tunneling was further supported by measuring the relative intensity of the PL contributions from the narrow and wide well at low pump power.

Presenter: Deborah Anne Opaon Lumantas