Probing the Inner Workings of Quantum Photonic Devices

Abstract

Scanning probe microscopy, including scanning spreading resistance microscopy, scanning capacitance microscopy and scanning voltage microscopy (SVM), is a novel and enabling tool to quantitatively probe internal dopant profile, voltage distribution and carrier distribution at nanometer scales. Scanning probe microscopy has been applied to a few representative photonic devices – buried heterostructure (BH) lasers, ridge waveguide lasers, terahertz (THz) quantum cascade lasers (QCL) and interband cascade lasers (ICL). The experimental results demonstrate that the unique SPM technique can reveal the inner workings, thus connect internal mechanism with external measures. The demonstration of resolving dynamic charge carrier density distribution and electric potential profile in an operating optoelectronic laser device is unprecedented and could open the door to many future applications in probing the underlying mechanisms for many puzzling issues such as sub-par performance and degradation in nanoelectronic devices, quantum devices and optoelectronic devices.