Analysis of intensity dependent near-bandedge absorption in semi-insulating 4H-SiC for photoconductive switch applications

作者：Meyers V; Chowdhury A R; Mauch D; Dickens J C; Neuber A A; Joshi R P^*

来源：Journal of Physics D: Applied Physics , 2017, 50(13): 135104.

DOI：10.1088/1361-6463/aa59aa

• SiC
• photoconductive switch
• intensity dependence
• absorption

We report on the intensity-dependent behavior of the absorption coefficient (alpha) in semiinsulating 4H-SiC material. Data from as-received samples show a monotonic decrease in a with incident energy density, with a pronounced change in slope at around 10 mJ cm(-2). Annealed samples, on the other hand, exhibit an experimental trend of increasing alpha with intensity. Qualitative explanation of the observed behavior is presented that probes the possible role of spontaneous and stimulated emission for as-received samples. With annealing, trap related recombination is strongly reduced leading to higher carrier densities and increased free-carrier absorption with incident intensity. The role of band-filling and permittivity changes are shown to be inconsequential, while changes in internal fields could contribute to decreases in absorption.

• 出版日期2017-4-5