Microstructure of Mg doped GaNAs alloys
Microstructure of Mg doped GaNAs alloys
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Mg掺杂GaNAs合金的微观结构
DOI：
10.1002/pssc.201200666
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Liliental-Weber Z
中科院分区：
文献类型：
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作者：
Liliental-Weber Z
在低温下通过MBE生长的Mg掺杂的GaN 1-xAsx样品的透射电子显微镜显示，半绝缘样品和具有高或低电导率的样品的结构发生了实质性变化。导电样品显示p型导电性，这是正热电势值的证据。所有的Mg掺杂样品显示相分离：立方GaAs和GaN晶粒（立方和一些六方的混合物）相内的非晶基体。最好的导电样品显示出嵌入到非晶基体中的具有高密度堆垛层错的立方GaAs晶粒。导电性较低的样品具有较低的样品的非晶相与结晶相的比率和低得多的堆垛层错密度。具有低Mg浓度或低As浓度的半绝缘样品显示GaAs和GaN晶粒彼此附着，没有证据表明它们之间存在非晶相。这些谷物中没有SF。GaAs晶粒之间GaN的存在可能导致半绝缘材料特性，因为GaN的p型掺杂更困难。（© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA，魏因海姆）
Transmission Electron Microscopy of Mg doped GaN1‐xAsxsamples, grown by MBE at low temperatures, show substantial structural changes for samples that are semi‐insulating and those with high or low conductivity. The conductive samples show p‐type conductivity as evidence from the positive thermopower values. All the Mg doped samples show phase segregation: cubic GaAs and GaN grains (a mixture of cubic and some hexagonal) phases within an amorphous matrix. The best conductive samples show cubic GaAs grains with high density of stacking faults embedded into an amorphous matrix. The samples that are less conductive have lower ratio of the amorphous to the crystalline phase of the samples and much lower density of stacking faults. Higher Mg concentration is expected in the amorphous parts of the samples The semi‐insulating samples that have either low Mg concentration or low As show grains of GaAs and GaN attached to each other with no evidence of the amorphous phase between them. There are no SFs in these grains. It is possible that the presence of the GaN between the GaAs grains lead to semi‐insulating material properties since p‐type doping of GaN is more difficult. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)