Mapping Charge Recombination and the Effect of Point-Defect Insertion in GaAs Nanowire Heterojunctions
Mapping Charge Recombination and the Effect of Point-Defect Insertion in GaAs Nanowire Heterojunctions
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GaAs 纳米线异质结中电荷复合的映射和点缺陷插入的影响
DOI：
10.1103/physrevapplied.16.044030
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发表时间：
2021
影响因子：
4.6
通讯作者：
Regan, B.C.
中科院分区：
文献类型：
--
作者：
Zutter, Brian T.;Kim, Hyunseok;Hubbard, William A.;Ren, Dingkun;Mecklenburg, Matthew;Huffaker, Diana;Regan, B.C.
电子设备对其组成半导体中的缺陷极为敏感，但在以前，在大块半导体中定位电子点缺陷是不可能的。本文应用扫描透射电子显微镜（STEM）电子束感应电流（EBIC）成像技术对纳米线肖特基二极管的电子缺陷进行了定位。在80或200 kV的非破坏性STEM加速电位下成像显示，六方纳米线表面附近的少数载流子扩散长度减小，从而表明该器件的电荷收集效率（CCE）受到表面缺陷的限制。用300 keV的STEM光束成像会引入空位-间隙（或Frenkel）缺陷，从而增加载流子复合并降低二极管的CCE。我们创建、定位并描述了单个插入事件，确定从肖特基界面插入7纳米的缺陷在整个纳米线器件上广泛地降低了CCE。因此，可变能量STEM EBIC成像允许对器件的电子-空穴重组进行良性映射和精确修改，从而实现受控实验，阐明扩展（一维和二维）和点（零维）缺陷对半导体器件性能的影响。
Electronic devices are extremely sensitive to defects in their constituent semiconductors, but locating electronic point defects in bulk semiconductors has previously been impossible. Here we apply scanning transmission electron microscopy (STEM) electron-beam-induced current (EBIC) imaging to map electronic defects in ananowire Schottky diode. Imaging with a nondamaging 80 or 200 kV STEM acceleration potential reveals a minority-carrier diffusion length that decreases near the surface of the hexagonal nanowire, thereby demonstrating that the device’s charge collection efficiency (CCE) is limited by surface defects. Imaging with a 300 keV STEM beam introduces vacancy-interstitial (or Frenkel) defects in thethat increase carrier recombination and reduce the CCE of the diode. We create, locate, and characterize a single insertion event, determining that a defect inserted 7 nm from the Schottky interface broadly reduces the CCE byacross the entire nanowire device. Variable-energy STEM EBIC imaging thus allows both benign mapping and pinpoint modification of a device’s electron-hole-recombination landscape, enabling controlled experiments that illuminate the impact of both extended (one- and two-dimensional) and point (zero-dimensional) defects on semiconductor device performance.