Bhowmick Mithun, Xi Haowen, Ullrich Bruno
Department of Mathematical and Physical Sciences, Miami University, Middletown, OH 45042, USA.
Department of Physics and Astronomy, Bowling Green State University, Bowling Green, OH 43403, USA.
Materials (Basel). 2021 Mar 27;14(7):1639. doi: 10.3390/ma14071639.
We are reporting an esoteric method to determine the optical bandgap of direct gap materials by employing Urbach's rule. The latter, which describes the slope of the band tail absorption in semiconductors, in its original version, cannot be employed to pinpoint the optical bandgap. Herein, however, we show that a modified form of Urbach's rule defines the optical bandgap, and therefore, enables the accurate determination of the optical bandgap energy, which turns out to be identical with the threshold energy for the band tail absorption. The model further produces an explicit expression for the absorption coefficient at the optical bandgap energy.
我们正在报告一种通过应用乌尔巴赫规则来确定直接带隙材料光学带隙的深奥方法。乌尔巴赫规则描述了半导体中带尾吸收的斜率，其原始版本无法用于精确确定光学带隙。然而，在此我们表明，乌尔巴赫规则的一种修正形式定义了光学带隙，因此能够精确测定光学带隙能量，结果发现该能量与带尾吸收的阈值能量相同。该模型还给出了光学带隙能量处吸收系数的显式表达式。
