【摘要】 利用室温下压电调制反射光（PzR）谱技术系统测量了N掺杂浓度为0.0%—3%的分子束外延生长GaN_xAs_1-x薄膜,并对图谱中所观察的光学跃迁进行了指认.在GaN0.005As0.995和GaN0.01As0.99薄膜的PzR谱中观察到此前只在椭圆偏振谱中才看到的N掺杂相关能态E1+Δ1+ΔN.当N掺杂浓度达到1%时,开始在PzR谱和PR谱中观测到Γ价带的轻重空穴分裂.给出室温下GaN_xAs_1-x材料的临界点能量随掺杂浓度的关系图,实验结果为E+和E两个跃迁同起源于L导带提供了室温下的佐证.更多还原

【Abstract】 Dilute GaN_xAs_1-x thin films with N concentration from 0.0% to 3% have been grown by molecular beam epitaxy. Piezomodulated reflectance （PzR） spectra of these thin films have been measured at room temperature, and optical transitions in PzR spectra have been well resolved. The N-related transition of E-1+Δ-1+Δ-N had been observed in PzR spectrum of GaN- 0.005 As- 0.995 and GaN- 0.01 As- 0.99 films. The well resolved split between heavy hole and light hole of Γ valence band is shown in PzR when the N doping level is up to 1%. The N concentration dependence of transition energies supports the model that both E-+ and E* originate from the L conductive band at room temperature.更多还原