Low-noise X-ray PIN photodiodes made of perovskite single crystals by solution-processed dopant incorporated epitaxial growth
Low-noise X-ray PIN photodiodes made of perovskite single crystals by solution-processed dopant incorporated epitaxial growth
复制标题
通过溶液处理掺杂剂外延生长由钙钛矿单晶制成的低噪声 X 射线 PIN 光电二极管
DOI：
10.1016/j.nanoen.2021.106311
复制
发表时间：
2021-07-12
期刊：
影响因子：
17.6
通讯作者：
Lei, Wei
中科院分区：
文献类型：
--
作者：
Wang, Xin;Xu, Yubing;Lei, Wei
由金属卤化物钙钛矿(MHPS)制成的X射线光电二极管直接将X射线光子转换为电子空穴对，在低成本和高X射线探测灵敏度方面显示出优势。然而，通过旋涂或蒸发沉积的晶格失配阻挡层不能完全限制大反向偏压下的暗电流和噪声电流。本工作采用溶液处理掺杂外延生长方法，在CH3NH3PbBr2.5Cl0.5MHP本征单晶的面上外延生长晶格匹配的n型MHPS(掺铋)和P型MHPS(掺银)，以形成足够的阻挡势垒。通过能量结构设计，电子/空穴阻挡层可以形成足够的电荷势垒，在较大的反向电场(超过500V cm(-1))和47Fahz(-0.5)(1 mm(2)，超过500V cm(-1))下，X射线PD显示出接近11nA cm(-2)的低泄漏暗电流密度。强大的外部电场使最先进的响应速度(下降)达到750 ns，X射线探测灵敏度达到36.0µC mGys(-1)cm(-2)，最低可探测剂量率为16nGys(-1)(40kVp)。这项工作将激励新的战略，以钙钛矿为基础，使用溶液处理方法制造高性能器件。这些发现还探索了基于MHPS的新一代低剂量、高动态X射线探测器。
X-ray photodiodes made of metal halide perovskites (MHPs) which directly convert X-ray photons into electron hole pairs have shown advantages in low-cost and high X-ray detection sensitivity. However, lattice-mismatched blocking layers deposited by spin-coating or evaporation cannot fully limit the dark current and noise current under large reverse bias. In this work, Solution-processed dopant incorporated epitaxial growth is employed to form sufficient blocking barriers through epitaxially growing lattice-matched n-type MHPs (bismuth-doped) and p-type MHPs (silver-doped) on opposite faces of intrinsic CH3NH3PbBr2.5Cl0.5 MHP single crystals. Through energy structure design, electron/hole blocking layers can form sufficient charges barriers, the X-ray PDs exhibit a low leakage dark current density of similar to 11 nA cm(-2) under large reverse electrical field (over 500 V cm(-1)) and noise current of 47 fAHz(-0.5) (1 mm(2), over 500 V cm(-1)). The large external electrical field enables a state-of-art response speed (fall) of 750 ns, large X-ray detection sensitivity of 36.0 mu C mGy(-1)cm(-2) and the lowest detectable dose rate of 16 nGys(-1)(40 kVp). This work will motivate new strategies to fabricate high-performance devices based on perovskites using solution-processed methods. These founding also explore a new generation of low dose and high dynamic X-ray detectors based on MHPs.