Band gap of GaN films grown by molecular‐beam epitaxy on GaAs and GaP substrates
Band gap of GaN films grown by molecular‐beam epitaxy on GaAs and GaP substrates
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GaAs 和 GaP 衬底上分子束外延生长 GaN 薄膜的带隙
DOI：
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
S. Hooper
中科院分区：
文献类型：
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作者：
D. Lacklison;J. Orton;I. Harrison;T. Cheng;L. Jenkins;C. T. Foxon;S. Hooper
关于宽禁带半导体GaN的立方（zinc‐ zinc）形式的能隙一直存在争议。本文报道了用改进的分子束外延方法在（001）GaAs和GaP衬底上淀积的六方晶系（纤锌矿）和立方晶系薄膜的带隙测量结果。与常规MBE的重要区别在于向生长膜供应氮的方法。这里使用在13 MHz下操作的RF氮等离子体源。通过X射线衍射监测薄膜的结构，并通过添加导致立方形式生长的As束来控制，否则薄膜以六方结构生长。在室温下通过光学反射率测量带隙，如通过当光子能量接近带边时干涉振荡的急剧减少所证明的，并且通过带边光致发光的观察所证实。六方晶系的Eg=3.42±0.02 eV，立方晶系的Eg = 3.22±0.02 eV。
There has been controversy concerning the energy gap of the cubic (zinc‐blende) form of the wide‐gap semiconductor GaN. Measurements are reported of the band gaps of both hexagonal (wurtzite) and cubic thin films deposited by a modified molecular‐beam‐epitaxy process on (001) GaAs and GaP substrates. The important difference from conventional MBE lies in the method of supplying nitrogen to the growing film. Here a rf nitrogen plasma source operating at 13 MHz is used. The structure of the films was monitored by x‐ray diffraction and controlled by the addition of an As beam which results in growth of the cubic form—otherwise films grow with the hexagonal structure. The band gaps were measured at room temperature by optical reflectivity, as evidenced by the sharp reduction in interference oscillations as the photon energy approached the band edge, and confirmed by the observation of band‐edge photoluminescence. The results can be summarized as Eg=3.42±0.02 eV for the hexagonal and 3.22±0.02 eV for the cubic...