Probing the large bandgap-bowing and signature of antimony (Sb) in dilute-antimonide III-nitride using micro-Raman scattering
Probing the large bandgap-bowing and signature of antimony (Sb) in dilute-antimonide III-nitride using micro-Raman scattering
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DOI：
10.1063/1.5109735
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发表时间：
2019-08
影响因子：
3.2
通讯作者：
F. Chowdhury;Z. Mi
中科院分区：
文献类型：
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作者：
F. Chowdhury;Z. Mi
稀锑iii氮化物（Sb < 1%）具有前所未有的宽范围带隙调谐和相关性质，为工程带结构、应变和极化提供了非凡的机会，并有望克服传统InGaN的基本问题，用于在深可见光谱范围内工作的高效光发射体，包括InN和GaN之间的大晶格失配（~ 11%）、大应变诱导极化场、且难以实现高效的p型传导。然而，到目前为止，对它们在稀Sb状态下的合成、结构和光学性质的基本理解仍然很大程度上未被探索。在此，我们研究了在n型Si衬底上通过等离子体辅助分子束外延生长的名义上未掺杂的稀锑化GaSbN纳米结构的室温非极化拉曼散射。后向散射几何中的非共振和近共振激发都表明，少量Sb掺入（<1%）对GaN的典型拉曼模式有很大影响。当Sb含量高达0.6%时，GaSbN薄膜中的A1（LO）模式的非线性递进频移从736 cm−1降至715 cm−1，这类似于稀释锑化GaSbN的大带隙减少。与Sb掺入相对应的拉曼特征可以通过光谱中的两个附加峰进一步观察到。对稀锑化GaSbN的结构和表面电荷特性的补充分析表明，拉曼模式波动可以用于进一步应变校正的合金中Sb含量的探测。稀锑iii氮化物（Sb < 1%）具有前所未有的宽范围带隙调谐和相关性质，为工程带结构、应变和极化提供了非凡的机会，并有望克服传统InGaN的基本问题，用于在深可见光谱范围内工作的高效光发射体，包括InN和GaN之间的大晶格失配（~ 11%）、大应变诱导极化场、且难以实现高效的p型传导。然而，到目前为止，对它们在稀Sb状态下的合成、结构和光学性质的基本理解仍然很大程度上未被探索。在此，我们研究了在n型Si衬底上通过等离子体辅助分子束外延生长的名义上未掺杂的稀锑化GaSbN纳米结构的室温非极化拉曼散射。后向散射几何中的非共振和近共振激发都揭示了典型的拉曼模式。
Dilute-antimonide III-nitrides (Sb < 1%), with their unprecedented and broad range tuning of bandgap and associated properties, provide extraordinary opportunities for engineering band structure, strain, and polarization and a significant promise to overcome the fundamental issues of conventional InGaN for efficient light emitters operating in the deep-visible spectral range, including the large lattice mismatch (∼11%) between InN and GaN, large strain-induced polarization field, and difficulty in realizing efficient p-type conduction. However, a fundamental understanding of their synthesis, structural, and optical properties at the dilute Sb regime has so far remained largely unexplored. Herein, we have investigated room-temperature, nonpolarized Raman scattering of nominally undoped dilute-antimonide GaSbN nanostructures, grown by plasma-assisted molecular beam epitaxy on n-type Si substrates. Both nonresonant and near-resonant excitation in backscattering geometry reveals that the typical Raman modes of GaN are largely affected due to a small amount of Sb incorporation (<1%). A nonlinear and progressive downward frequency shift of the A1(LO) mode in GaSbN epilayers had been derived from 736 cm−1 to 715 cm−1 for Sb composition up to 0.6%, which is analogous to the large bandgap reduction of dilute-antimonide GaSbN. Raman signatures corresponding to Sb incorporation can be observed further via two additional peaks in the spectra. Complementary analysis on structural and surface charge properties of dilute-antimonide GaSbN suggests that the Raman-mode fluctuations can be useful for probing Sb contents in the alloy with further strain correction.Dilute-antimonide III-nitrides (Sb < 1%), with their unprecedented and broad range tuning of bandgap and associated properties, provide extraordinary opportunities for engineering band structure, strain, and polarization and a significant promise to overcome the fundamental issues of conventional InGaN for efficient light emitters operating in the deep-visible spectral range, including the large lattice mismatch (∼11%) between InN and GaN, large strain-induced polarization field, and difficulty in realizing efficient p-type conduction. However, a fundamental understanding of their synthesis, structural, and optical properties at the dilute Sb regime has so far remained largely unexplored. Herein, we have investigated room-temperature, nonpolarized Raman scattering of nominally undoped dilute-antimonide GaSbN nanostructures, grown by plasma-assisted molecular beam epitaxy on n-type Si substrates. Both nonresonant and near-resonant excitation in backscattering geometry reveals that the typical Raman modes o...