Paul Thompson

Heriot-Watt University · Department of Physics

Quantum confined Stark effect p‐i‐n waveguide modulators, grown on GaAs substrates by molecular beam epitaxy and using an undoped ZnSe/ZnCdSe multiquantum well structure as the guiding layer, have exhibited intensity modulation at wavelengths of 496 and 501 nm with extinction ratios of 6 and 4, respectively. These same devices have also demonstrate...

This paper reports on the growth of ZnSe and ZnCdSe epilayers on GaAs(2 1 1)B substrates by molecular beam epitaxy. The layer quality, as determined by the PL spectra, depends critically on the reconstruction of the GaAs surface before growth. Two surface reconstructions are suggested for the (2 1 1)B surface which correspond to the two different c...

Over the past few years nitrogen has been shown to be by far the best dopant to use in the production of p-type ZnSe, although it is often highly compensated. This review describes the evidence for compensation in ZnSe:N due to the presence of selenium vacancy complexes and also more recent evidence for the presence of other compensating donors and...

The compensating accepters and donors in nitrogen delta-doped ZnSe epilayers grown by molecular beam epitaxy using a nitrogen rf-plasma source are studied by means of photoluminescence and photoluminescence excitation spectroscopy. A deep acceptor and a deep donor with ionization energies of similar to 170 and similar to 88 meV are reported for the...

Photoluminescence excitation spectroscopy (PLE) of nitrogen doped ZnSe epilayers is reported here for the first time. The dependence of the PLE spectra on the net acceptor concentration in ZnSe:N and the temperature has been investigated. A new radiative transition at 2.732 eV is revealed in highly doped ZnSe:N, and is attributed to a transition be...

In this paper we report the first waveguide modulator, grown on a GaAs substrate by molecular beam epitaxy, to use an undoped ZnSeZnCdSe multi quantum well structure as the guiding layer with doped ZnSe layers acting as the surrounding cladding. The quantum confined Stark effect was observed in this device and used to produce an intensity modulatio...

The piezoelectric effect has been demonstrated for the first time in strained ZnSeZnCdSe quantum wells grown on (211)B GaAs substrates. A piezoelectric field strength of 1.1 × 105V/cm has been observed in Zn0.8Cd0.2Se quantum wells that have a 1.3% lattice mismatch with the substrate.

This letter reports the growth and characterization of ZnSe:N layers by atomic layer epitaxy (ALE) using a nitrogen rf‐plasma source. The ALE‐grown ZnSe:N layers have been investigated in terms of in situ reflection high electron energy diffraction and ex situ capacitance–voltage profiling and photoluminescence spectroscopy. The net acceptor concen...

The compensating acceptors and donors in nitrogen δ‐doped ZnSe epilayers grown by molecular beam epitaxy using a nitrogen rf‐plasma source are studied by means of photoluminescence (PL) and photoluminescence excitation spectroscopy (PLE). The temperature dependence of PL and PLE spectra obtained from the nitrogen δ‐doped layers is investigated in d...

An optical projection system has been developed which allows patterning of both layer thickness and donor concentration in epitaxial films of ZnSe during growth by molecular beam epitaxy. Doping features with a period as small as 40 μ m have been produced and it appears possible to reduce this by at least one order of magnitude. Such in-situ techni...

In this paper, we report the first observation of a II-VI symmetric self-electro-optic device (SEED) operating as an optical switch at a wavelength of 488 nm at room temperature. Quantum confined Stark effect modulators based on ZnSe/ZnCdSe p-i-n structures were fabricated by molecular beam epitaxy and used in the symmetric mode where one modulator...

Optical bistability at room temperature has been observed for the first time in a II‐VI semiconductor self‐electro‐optic effect device fabricated by molecular beam epitaxy. The optical switch is based on a ZnSe/ZnCdSe multiple quantum well structure situated within a p‐n junction and the devices operate at 488 nm in the blue‐green spectral region.