The detection of ultraviolet (UV) radiation with effective performance and robust stability is essential to practical applications. Metal halide singlecrystal perovskites (ABX 3 ) are promising next-generation materials for UV detection. The device performance of all-inorganic CsPbCl 3 photodetectors (PDs) is still limited by inner imperfection of crystals grown in solution. Here wafer-scale single-crystal CsPbCl 3 thin films are successfully grown by vapor-phase epitaxy method, and the as-constructed PDs under UV light illumination exhibit an ultralow dark current of 7.18 pA, ultrahigh ON/OFF ratio of ≈5.22 × 10 5 , competitive responsivity of 32.8 A W −1 , external quantum efficiency of 10867% and specific detectivity of 4.22 × 10 12 Jones. More importantly, they feature superb long-term stability toward moisture and oxygen within twenty-one months, good temperature tolerances at low and high temperatures. The ability of the photodetector arrays for excellent UV light imaging is further demonstrated.

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The ancient aeolian sand has been regarded as an indicator for the formation and evolution of a desert in the past. Kumtagh Desert is located at the northern fringe of Qinghai-Tibet Plateau. The first integrated scientific investigation to the desert was carried out during the period of 2004−2006. Kumtagh Desert is an ideal natural model for studying the formation and evolution of the desert because the Quaternary strata containing ancient aeolian sands are widely distributed. The integrated field investigation and studies on sedimentary, chronology and palynology of typical profiles named Suosuo gully, Xiaoquan gully and gravel body with ancient aeolian sand layers showed that Kumtagh Desert was probably formed as early as 2,097.7±314.7 ka BP. During the period of 386.9±58.0 ka BP to 285.9±42.9 ka BP, the desert largely expanded and formed its modern distribution pattern. The desert was originally developed in the southwest, subsequently, expanded to the north and northeast. The sedimentary facies of Suosuo gully profile revealed that the desert experienced at least 19 cycles of advance and inverse processes of desertification with an average period of 110 ka in the Quaternary. The neotectonic movements played an important role in the formation, development and geomorphology of the desert. On one hand, the movements caused the formation of intermontane fault basin, which was further developed towards the closed drought basin, and caused the formation of natural environment. On the other hand, under the control of surrounding faults, the unique broom-shaped desert landscape was formed, and the gullies and sand ridges in this region experienced an abrupt directional change from north by west to north by east at the location of 39°45′−39°55′N. The unique landscape of gravel body that occurred widely in the northern desert was formed after 285.9±42.9 ka BP. The results in this paper provide the scientific basis for studying the formation age and evolutionary process under the dry climate and environment in the northwestern China, and the uplifting of Qinghai-Tibet Plateau as well as its responses to the global climate changes.

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