Three-Photon Absorption Spectra and Bandgap Scaling in Direct-Gap Semiconductors
Sepehr Benis, Claudiu M. Cirloganu, Nicholas Cox, Trenton Ensley, Honghua Hu, Gero Nootz, Peter D. Olszak, Lazaro A. Padilha, Davorin Peceli, Matthew Reichert, … 展开作者
Sepehr Benis, Claudiu M. Cirloganu, Nicholas Cox, Trenton Ensley, Honghua Hu, Gero Nootz, Peter D. Olszak, Lazaro A. Padilha, Davorin Peceli, Matthew Reichert, Scott Webster, Milton Woodall, David J. Hagan, Eric W. Van Stryland
This paper presents three-photon absorption (3PA) measurement results for nine direct-gap semiconductors, including full 3PA spectra for ZnSe, ZnS, and GaAs. These results, along with our theory of 3PA using an 8-band Kane model (4 bands with double spin degeneracy), help to explain the significant disagreements between experiments and theory in the literature to date. 3PA in the 8-band model exhibits quantum interference between the various possible pathways that is not observed in previous 2-band theories. We present measurements of degenerate 3PA coefficients in InSb, GaAs, CdTe, CdSe, ZnTe, CdS, ZnSe, ZnO, and ZnS. We examine bandgap, Eg, scaling using 2-band tunneling and perturbation theories that show agreement with the predicted Eg^-7 dependence; however, For those semiconductors for which we measured full 3PA spectra, we observe significant discrepancies with both 2-band theories. On the other hand, our 8-band model shows excellent agreement with the spectral data. We then use our 8-band theory to predict the 3PA spectra for 15 different semiconductors in their zincblende form. These results allow prediction and interpretation of the 3PA coefficients for various narrow to wide bandgap semiconductors.
Nanosecond light induced, thermally tunable transient dual absorption bands in a-Ge5As30Se65 thin film
在这篇文章中，我们首次观察到纳秒激光诱导的瞬态双吸收带，一个在带隙（TA 1）和另一个在亚带隙（TA 2）区域的a-Ge 5 As 30 Se 65薄膜。引人注目的是，这些带是热可调的，并表现出独特的对比特性：随着温度的升高，TA 1的幅度减小，而TA 2的幅度增加。此外，这些带的衰减动力学强烈地受温度的影响，这意味着强烈的温度依赖性激子复合机制。诱导吸收与激光能量密度呈二次函数关系，衰减时间常数与激光能量密度呈线性关系。
