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We show that a 4 μm thick GaN layer grown by metal-organic vapour phase epitaxy can be transformed into a well-organized array of GaN nanowires (NWs) using displacement Talbot lithography and selective area sublimation. The optical quality of the GaN NWs obtained by this method is attested by their room temperature photoluminescence and the observation of lasing under optical pumping with a minimum excitation power density threshold of 2.4 MW cm−2.

Infrared photodetectors have been fabricated based on InAs/GaAs self-assembled quantum dot (QD) layers, with various QD densities and doping levels. Dark currents have been measured as a function of applied bias and temperature. They show a clear activation energy, which decreases as the QD shell filling increases. Its absolute value and dependence on applied bias indicate that electrons tunnel from QD levels into the wetting layer of the next period. Resonant structures in the current–voltage curve and in its first derivative confirm the tunneling through the GaAs barrier. Negative differential resistances are observed in highly doped samples at low temperature.