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HL: Halbleiterphysik

HL 57: Poster IIa

HL 57.28: Poster

Dienstag, 8. März 2005, 16:30–19:00, Poster TU E

Quantum Optical Studies of Single InP/GaInP Quantum Dots — •Gareth Beirne¹, Peter Michler¹, and Heinz Schweizer² — ¹5th Institute of Physics, University of Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany — ²4th Institute of Physics, University of Stuttgart, Pfaffenwaldring 57, 70550 Stuttgart, Germany

Using the Stranski-Krastanow growth mode, the MOVPE deposition of InP on GaInP can be used to produce 2 distinct types of coherently strained quantum dots (QDs). We refer to the structures with an average height of 5 nm as type A dots and the structures with an average height of 20 nm as type B dots. The type B structures are expected to exhibit a Type II band alignment, with the electron confined in the dot and the hole located in the wetting layer or barrier material. Under continuous wave excitation at 4 K (1.7763 eV, 15.9 kW cm-2), broad (FWHM = 0.50 meV) and intense (131,000 counts/sec) exciton emission at 1.6558 eV was observed from a single type B InP/GaInP QD, contained in a 500 nm (diameter) mesa structure. Subsequent continuous and pulsed photon statistics measurements performed on the same dot display clear antibunching effects, and in the pulsed case, single photon emission on demand was achieved at a wavelength of 748.8 nm (a value closely matching the optimal detection wavelength of silicon-based single photon detectors). Finally, we have investigated whether the addition of aluminium to the barrier material extends the temperature range over which single photon emission may be realised using type B InP QDs.