Room temperature self-organized quantum dot transistors

Semiconductor quantum dots (QDs), due to the discrete nature of their density of states, are very attractive for optoelectronic and electronic devices. Quantum dot single electron transistors are highly sought after for low power and high-density semiconductor memory and logic devices. Strained layer growth in the Stranski-Krastanow growth mode, referred to as self-organized growth, is a promising method for producing regular arrays of dislocation free quantum dots without post-growth transistors at low temperature. There have been a variety of reports on the nonlinear transport properties of quantum dot transistors at low temperature. We report a novel field-effect transistor with quantum dots in close proximity to a quantum well channel, demonstrating steps and nonlinear transport properties at room temperature. MODFET structures were grown by MBE, consisting of an InGaAs quantum well channel grown on GaAs, with a delta-doped AlGaAs barrier. A layer of self-organized InAs quantum dots were grown 2.5 nm above the channel and the structure was delta-doped at n=1×1(12) cm/sup -2/ at a distance of 5 nm above the channel. Transistors were fabricated with 0.3 μm gates through e-beam lithography, optical lithography, wet chemical etching, and metallization.