Technological advances have unfurled the previously unused terahertz frequency band for numerous promising applications. It has a special position in the spectrum between infrared and microwave rays that makes it acquire unique features of safety, broadband, penetration, and low energy. In this paper, we portray a diverse survey on salient features of THz band and its wide range of applications beyond fifth generation (B5G) and towards the 6G communication systems. First, we present various features of THz bands and how it is applicable to 6G networks. Next, we discuss the limitations of THz technology followed by the state of art recently proposed techniques to overcome those limitations. Further, we discuss a broad range of THz applications in different domains such as spectroscopy, biomedical and military applications. Finally, we present the recent advancement in different THz detectors and their comparisions. Moreover, we present a review on the challenges for Terahertz range communication identified in existing research and discuss some future research directions.