InGaAs quantum wires ͑QWRs͒ with cross sections as narrow as 10 nmϫ20 nm have been fabricated on a (311)A InP V-grooved substrate under an As 2 source. Trench-type InGaAs QWRs consist of (111)A and (331)B facets with an angle of about 22°. Cathode-luminescence and photoluminescence measurements confirmed the luminescence peak arising from the QWRs.

Articles you may be interested inNegative differential resistance effects of trench-type InGaAs quantum-wire field-effect transistors with 50-nm gate-length Appl. Phys. Lett. 83, 701 (2003); 10.1063/1.1595150Trench-type InGaAs quantum-wire field effect transistor with negative differential conductance fabricated by hydrogen-assisted molecular beam epitaxy Observation of negative differential resistance of a trench-type narrow InGaAs quantum-wire field-effect transistor on a (311)A InP substrate Negative differential resistance of a ridge-type InGaAs quantum wire field-effect transistor Trench-type narrow InGaAs quantum-wire field-effect transistors ͑QWR-FETs͒ have been fabricated on ͑311͒A InP V-groove substrates by hydrogen-assisted molecular-beam epitaxy. Enhanced negative differential resistance ͑NDR͒ effects with a peak-to-valley ratio ͑PVR͒ as high as 13.3 have been observed at an onset voltage of 0.16 V in the QWR-FETs at 24 K. The PVR increased with reductions in the InGaAs epitaxial layer thickness, which caused an enhanced mobility difference between the QWR and side quantum wells ͑QWs͒. This forms a velocity modulation transistor based on the real-space transfer of electrons from the high mobility QWR to the low mobility side QWs. The NDR effects were observed up to 230 K as the gate length was decreased to 50 nm. A unique feature of the QWR-FET is that NDR effects are controllable with the gate bias in a three-terminal configuration.

Articles you may be interested inEnhanced peak-to-valley current ratio in In Ga As ∕ In Al As trench-type quantum-wire negative differential resistance field-effect transistors Photoconductive characteristics in a trench-type InGaAs quantum-wire field effect transistor J. Vac. Sci. Technol. B 22, 1523 (2004); 10.1116/1.1752911Trench-type InGaAs quantum-wire field effect transistor with negative differential conductance fabricated by hydrogen-assisted molecular beam epitaxy Observation of negative differential resistance of a trench-type narrow InGaAs quantum-wire field-effect transistor on a (311)A InP substrate Negative differential resistance of a ridge-type InGaAs quantum wire field-effect transistor

The surface diffusion length of Ga adatoms under As2 or As4 flux has been measured using V-grooved GaAs (001) substrates in molecular beam epitaxy. The diffusion length on the (001) surface toward the [110] direction, of Ga adatoms under As2 flux is about half of that under As4 flux. A smaller number of Ga atoms under As2 flux migrate to the (001) ridge surface from the sidewall surface than those under As4 flux. Furthermore, the Al0.6Ga0.4As layer on the V-grooved GaAs substrate grown under As2 flux preserve the V-shape, whereas the V-shape cannot be preserved during the growth under As4 flux. The GaAs quantum wire structures which have Al0.6Ga0.4As barrier layeres are fabricated under As2 flux.

Ridge-type InGaAs/InAlAs quantum-wire field-effect transistors are realized by selective molecular-beam epitaxy and their transport characteristics are studied. An analysis of the depopulation of one-dimensional subbands in these structures reveals little evidence for sidewall depletion, and yields an estimate for the carrier density in good agreement with that found in two-dimensional InGaAs/InAlAs heterojunctions. Subband splittings as large as 7.4 meV are obtained in the wires, indicating their excellent one-dimensional transport properties.