High-Mobility Metastable Rock-Salt Type (Sn,Ca)Se Thin Film Stabilized by Direct Epitaxial Growth on a YSZ (111) Single-Crystal Substrate
High-Mobility Metastable Rock-Salt Type (Sn,Ca)Se Thin Film Stabilized by Direct Epitaxial Growth on a YSZ (111) Single-Crystal Substrate
复制标题
通过在 YSZ (111) 单晶衬底上直接外延生长稳定的高迁移率亚稳态岩盐型 (Sn,Ca)Se 薄膜
DOI：
10.1021/acsami.2c01464
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发表时间：
2022
影响因子：
9.5
通讯作者：
and Toshio Kamiya
中科院分区：
文献类型：
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作者：
Xinyi He;Jinshuai Chen;Takayoshi Katase;Makoto Minohara;Keisuke Ide;Hidenori Hiramatsu;Hiroshi Kumigashira;Hideo Hosono;and Toshio Kamiya
亚稳立方(Sn1-xPbx)Se的x≥为0.5时，由于其类似狄拉克的电子态，有望成为一种高迁移率半导体，但它具有过高的载流子浓度∼1019 cm-3，不适合用于薄膜晶体管和太阳能电池等半导体器件。此外，由于铅的高蒸汽压，(Sn1-xPbx)Se薄膜需要复杂的合成过程。本文报道了用Case合金化的亚稳立方(Sn1-xCax)Se薄膜的直接生长，它比PbSe具有更宽的禁带和更低的蒸汽压。采用脉冲激光沉积技术在YSZ(111)单晶衬底上稳定生长了x=0.4~0.8的立方(Sn1-xCax)Se外延膜。(Sn1-xCax)Se具有直接跃迁带隙，通过改变x可以在1.4 eV(x=0.4)到2.0 eV(x=0.8)之间改变带隙能量。当x=0.4~0.6时，薄膜表现为p型导电，空穴载流子浓度较低，∼为10 17 cm-3。霍尔迁移率分析表明，空穴输运以180°旋转磁畴结构为主，这是(111)取向外延薄膜特有的。然而，(Sn0.6Ca0.4)Se薄膜的晶内载流子迁移率高达322cm2/(Vs)，远高于热力学稳定的SnSe和其他锡基层状半导体薄膜的室温载流子迁移率。因此，目前的结果证明了高迁移率(Sn1-xCax)Se薄膜通过简单的薄膜沉积工艺在半导体器件应用中的潜力。
Metastable cubic (Sn1–xPbx)Se withx≥ 0.5 is expected to be a high mobility semiconductor due to its Dirac-like electronic state, but it has an excessively high carrier concentration of ∼1019cm–3and is not suitable for semiconductor device applications such as thin film transistors and solar cells. Further, thin films of (Sn1–xPbx)Se require a complicated synthesis process because of the high vapor pressure of Pb. We herein report the direct growth of metastable cubic (Sn1–xCax)Se films alloyed with CaSe, which has a wider bandgap and lower vapor pressure than PbSe. The cubic (Sn1–xCax)Se epitaxial films withx= 0.4–0.8 are stabilized on YSZ (111) single crystalline substrates by pulsed laser deposition. (Sn1–xCax)Se has a direct-transition-type bandgap, and the bandgap energy can be varied from 1.4 eV (x= 0.4) to 2.0 eV (x= 0.8) by changingx. These films withx= 0.4–0.6 show p-type conduction with low hole carrier concentrations of ∼1017cm–3. Hall mobility analysis suggests that the hole transport would be dominated by 180° rotational domain structures, which is specific to (111) oriented epitaxial films. However, it, in turn, clarifies that the in-grain carrier mobility in the (Sn0.6Ca0.4)Se film is as high as 322 cm2/(Vs), which is much higher than those in thermodynamically stable layered SnSe and other Sn-based layered semiconductor films at room temperature. Therefore, the present results prove the potential of high mobility (Sn1–xCax)Se films for semiconductor device applications via a simple thin-film deposition process.