This article reviews the recent advancements in photodetectors based on two-dimensional (2D) materials and heterostructures, focusing on their design and performance analysis. The demand for sophisticated, self-powered, compact, ultrafast, cost-effective, and broadband light sensors has driven significant research in this field. The review highlights the importance of device architecture in photoinduced charge carrier generation and separation, particularly in 2D materials such as graphene and other atomically thin 2D materials. It discusses the light-sensing properties of various 2D materials and their heterostructures across different spectral ranges, including UV-NIR, SWIR, MWIR, LWIR, and THz. The article also examines novel photodetector concepts, such as those based on the pyro-phototronic effect, localized surface plasmon resonance (LSPR), photothermoelectric effect, waveguide-integrated silicon-2D PDs, metal-2D-metal PDs, and organic material PDs. The review concludes with a discussion on current challenges and potential solutions to enhance the figures of merit of photodetectors, emphasizing the need for self-powered, high-performance, and cost-effective devices.This article reviews the recent advancements in photodetectors based on two-dimensional (2D) materials and heterostructures, focusing on their design and performance analysis. The demand for sophisticated, self-powered, compact, ultrafast, cost-effective, and broadband light sensors has driven significant research in this field. The review highlights the importance of device architecture in photoinduced charge carrier generation and separation, particularly in 2D materials such as graphene and other atomically thin 2D materials. It discusses the light-sensing properties of various 2D materials and their heterostructures across different spectral ranges, including UV-NIR, SWIR, MWIR, LWIR, and THz. The article also examines novel photodetector concepts, such as those based on the pyro-phototronic effect, localized surface plasmon resonance (LSPR), photothermoelectric effect, waveguide-integrated silicon-2D PDs, metal-2D-metal PDs, and organic material PDs. The review concludes with a discussion on current challenges and potential solutions to enhance the figures of merit of photodetectors, emphasizing the need for self-powered, high-performance, and cost-effective devices.