This presentation highlights the latest technology advancement on 3-dimensional position-sensitive room-temperature CdZnTe (CZT) semiconductor gamma-ray imaging spectrometers. Sustained advancement on CZT detector technology, including larger detection volume, digital application specific integrated circuit (H3DD-UM ASIC) and integrated electronic data acquisition systems will be described, as well as research and development on alternative semiconductor gamma-ray spectrometers. The applications of 3D CZT detectors will be summarized in national security, nuclear power industry, international nuclear safeguard and non-proliferation, space exploration, and medical imaging. The operational principle and unique capabilities will be introduced to explore potential applications in fundamental physics and astrophysics.