Dr Helen Springbett

My research at the Cambridge Centre for Gallium Nitride focused on improving materials for blue single photon sources. The overall aim of the blue single photon source work in the GaN group is to develop nitride quantum dot single photon sources from the early prototype stage towards a working quantum technology. On-demand photons are a necessity for applications such a quantum cryptography and quantum computing, and GaN offers the advantages of access to the blue and green spectral regions, tuneable emission, and higher operation temperatures. The wurtzite structure of GaN holds a spontaneous polarization and a large piezoelectric constant along the [0001] direction, which leads to polarity in strained c-plane quantum dot structures. This reduces the radiative recombination efficiency of devices grown along such directions via the quantum-confined Stark effect. For this reason, my work was focusing on structures grown along non-polar directions.