Continued dimensional scaling of semiconductor devices has driven information technology into vastly diverse applications. As the size of devices approaches fundamental limits, metrology techniques with nanometre resolution and threedimensional (3D) capabilities are desired for device optimisation. For example, the performance of an ultra-scaled transistor can be strongly influenced by the local electric field and strain. Here we study the spectral response of single erbium ions to applied electric field and strain in a silicon ultra-scaled transistor. Stark shifts induced by both the overall electric field and the local charge environment are observed. Further, changes in strain smaller than 3×10 -6 are detected, which is around two orders of magnitude more sensitive than the standard techniques used in the semiconductor industry. These results open new possibilities for non-destructive 3D mapping of the local strain and electric field in the channel of ultra-scaled transistors, using the single erbium ions as ultra-sensitive atomic probes.Complementary metal-oxide-semiconductor (CMOS) has been the most widely used technology in very-large-scale integration for decades due to its high noise immunity and low static power consumption. As integrated circuits scale towards the sub-10-nm nodes and clock speeds reach above 3-4 GHz, heating becomes a significant limit for traditional CMOS devices 1 . Thus, a high carrier mobility, which is strongly influenced by the local environment inside the channel, is becoming a crucial requirement for improving transistor performance. Recently in the semiconductor industry, there has been a departure from the traditional planar device geometry 2 . The multilayer complexity has made it necessary to precisely control the electric field and strain in the device channel as they can strongly affect the carrier mobility 3 . Yet a major problem arises: as the device size shrinks further, process variations 4 make it increasingly difficult to predict transistor properties only with finite element simulations. Therefore, non-destructive 3D strain and electric field mapping in the channel of ultra-scaled

Low threshold electrically pumped random lasers were realized in n-ZnO/p-MgZnO core–shell nanowire heterostructures.

Intense electroluminescence has been obtained from ZnO nanowires with holes injected from p-ZnO:Sb prepared via a high pressure high temperature method.