Low-Temperature-Processed Hybrid Nanomaterials for Semiconductor Devices

Due to their excellent electrical and optical properties, inorganic single-crystal semiconductors see application in high-efficiency solar cells, photodetectors, and lasers. Unfortunately, they require complex high-temperature fabrication processes that have limited capability in scale-up manufacturing. There remains an unmet need for new high-performance semiconductors that can be deposited using inexpensive and scalable manufacturing techniques. In this thesis, I demonstrate the fabrication, characterization, and device integration of an emerging semiconductor material: hybrid organic-inorganic trihalide perovskites. I show that this material can be formed with low-cost, large-area-compatible fabrication techniques, including solution-processing and atomic layer deposition. I first show that solution-processed perovskites are a promising material for low-cost photodetectors. I demonstrate the fast and sensitive detection of light enabled by the interface engineering of a new dark-current-reducing composite bilayer. This photodetector exhibited a peak specific detectivity exceeding 1E12 Jones, approaching that of commercial large-area silicon photodiodes, and was stable throughout the detection of over 1 billion transient light pulses over a 24-hour period. Utilizing the strong nonlinear absorption in these perovskites, I then demonstrate for the first time that this material can be used for two-photon photodetection. I deploy this photodetector to measure accurately the pulse width of an ultrafast laser. I next show that organic-inorganic trihalide perovskites are excellent materials for photonic sources. I report for the first time the optical gain coefficient of this material: 3200 Âą 830 cm-1. This critical parameter for optoelectronic devices is comparable to that of GaAs, a leading high-performance single-crystal material. To achieve the first perovskite spherical resonator laser, I developed a new fabrication strategy, which I termed perovskite-ALD, that enabled conformal and uniform layers of perovskites to be deposited onto spherical substrates, enabling lasing. I conclude with a discussion of the impact of my research on the expanding field of perovskite devices and an evaluation of the prospects of perovskite diodes as photonic sources. I show that perovskites are already demonstrating progress as high-brightness light-emitting-diodes and analyze new avenues forward. I lastly discuss the key ingredients needed for the realization of the first solution-cast electrically-driven laser and assess the promise of perovskites for this important application.Ph.D