Coulomb blockade: Toward charge control of self-assembled GaN quantum dots at room temperature

Abstract

We present capacitance–voltage [C(V)] measurements of self-assembled wurtzite-GaN quantum dots (QDs). The QDs are embedded in a charge-tunable diode structure and were grown by molecular beam epitaxy in the Stranski–Krastanov growth method. The internal electric fields present in GaN and its alloys together with its wide bandgap make this material system an ideal candidate for high-temperature quantum applications. Charges and the internal electric fields influence the energy spacing in the QDs. We correlate photoluminescence measurements with C(V) measurements and show single-electron charging of the QDs and a Coulomb blockade energy of around 60 meV at room temperature. This finding demonstrates the possibility of quantum applications at room temperature.