4.4 Motivation for 3D Confined Coaxial Nanolasers -- 4.5 Design and Fabrication of Optically Pumped Coaxial Nanolasers -- 4.6 Emission Characterization of High [beta]-factor Coaxial Nanolasers -- 4.7 Emission Characterization of Unity [beta]-factor Coaxial Nanolasers -- 4.8 Rate Equation Analysis of Unity [beta]-factor Coaxial Nanolasers -- 4.9 Perspective on Plasmonic Mode Nanolasers -- 5 Antenna-inspired Nano-patch Lasers -- 5.1 Optical Mode and Radiation Pattern of Nanopatch Lasers -- 5.2 Experimental Demonstration of Optically Pumped Nanopatch Laser -- 5.3 Toward Low-threshold, Engineerable Radiation Pattern, and Electrical Pumping -- 6 Active Medium for Semiconductor Nanolasers: MQW vs. Bulk Gain -- 6.1 Current Injection in Semiconductor Nanolasers -- 6.2 Optical Cavity and Material Gain Optimization -- 6.3 Reservoir Model for Semiconductor Lasers -- 6.4 Laser Rate-equation Analysis with the Reservoir Model -- 6.5 Discussion -- 7 Electrically Pumped Nanolasers -- 7.1 Optical Mode Design with Realistic Geometrical Parameters -- 7.2 Cylindrical Nanolasers with InP Undercut -- 7.3 Cylindrical Nanolasers without InP Undercut -- 7.4 Cubical Nanolasers without InP Undercut -- 8 Multi-physics Design for Nanolasers -- 8.1 Simulation of Nanolasers' Electrical and Thermal Performance -- 8.1.1 Ohmic Resistance -- 8.1.2 Calculation of Self-heating -- 8.1.3 Simulation of Nanolaser Heat Dissipation -- 8.2 Choice and Fabrication Techniques of Dielectric Material for Thermal Management -- 8.3 Comparison of Device Performance with Different Dielectric Shield Material -- 8.3.1 Optical Performance -- 8.3.2 Electrical and Thermal Performance -- 8.3.3 Discussions -- 8.4 Preliminary Experimental Validation and Analysis with Al[sub(2)]O[sub (3)] Shield -- 8.4.1 Experimental Validation and Optical Mode Analysis -- 8.4.2 Electrical and Thermal Analysis of Measured Device