Tube-in-Furnace Grown Scalable Perovskite Single-Crystal Thin Films with Ultrahigh Optical Gain and Polarization Sensitivity

Revolutionary perovskite single-crystal thin films offer exceptional potential in optoelectronic and electronic applications due to their unique structural properties and tunable bandgap. Instability, intricate fabrication, and high costs pose significant barriers to their practical application in devices such as solar cells, light-emitting diodes (LEDs), and sensors. Here, we present a "tube in the furnace" chemical vapor deposition (TIF-CVD) method to efficiently fabricate high-quality, stable, and uniform perovskite single-crystal thin films, offering a promising solution to overcome these limitations and paving the way for their integration into next-generation optoelectronic devices. With ultralow trap density (4.35 × 10⁹ cm^-3) and higher crystallinity, our method achieves an ultralow threshold of amplified spontaneous emission (ASE) and an exceedingly high gain coefficient (g ∼ 3612.29 cm^-1), which represents one of the highest values reported in halide lead perovskite thin films. We further explore the polarization-sensitive photoluminescence (PL), absorption, and photoresponsivity of the thin films, demonstrating their unique optoelectronic behavior under varying polarization states. Our scalable, simple, and cost-effective process for producing single-crystal thin films has potential for next-generation optoelectronic devices, including perovskite lasers, LEDs, and photodetectors (PDs), with a large cavity, enabling larger-scale crystal growth for practical and widespread use.