Deep level defects in CdTe materials studied by thermoelectric effect spectroscopy and photo-induced current transient spectroscopy
Deep level defects in CdTe materials studied by thermoelectric effect spectroscopy and photo-induced current transient spectroscopy
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DOI：
10.1088/0268-1242/22/5/014
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发表时间：
2007-03
影响因子：
1.9
通讯作者：
H. Elhadidy;J. Franc;P. Moravec;P. Höschl;M. Fiederle
中科院分区：
文献类型：
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作者：
H. Elhadidy;J. Franc;P. Moravec;P. Höschl;M. Fiederle
利用热电效应光谱（tee）和光感应电流瞬态光谱（PICTS）研究了垂直梯度冷冻法生长的半绝缘碲化镉晶体的深层能级。在不同升温速率下测量了90 ~ 400 K温度范围内的tee光谱。利用升温速率法得到了能级的位置和俘获截面。结果发现，在浅层给体（Cl, in）掺杂的样品中，近中隙能级的俘获截面值较低（≈10−15−10−17 cm2），为空穴陷阱。掺杂深层给体（Ge, Sn）的样品具有更高的中隙能级捕获截面（≈10−13 cm2），其作用为电子陷阱。将TEES结果与PICTS方法进行比较，结果表明，尽管两种方法的电离能评估值是相当的，但PICTS技术给出的捕获截面比TEES系统地高大约两个数量级。
The deep levels in semi-insulating CdTe crystals grown by vertical gradient freezing technique were studied using thermoelectric effect spectroscopy (TEES) and photo-induced current transient spectroscopy (PICTS). The measurement of TEES spectra in the temperature range 90–400 K was performed at different heating rates. The positions of the levels and their capture cross-sections were obtained by using the heating rate method. It was found that near midgap levels in samples doped with shallow donors (Cl, In) have a low value of capture cross section (≈10−15 − 10−17 cm2) and are hole traps. Samples doped with a deep donor (Ge, Sn) have a much higher capture cross section of the midgap level (≈10−13 cm2), which acts as an electron trap. Comparison of the TEES results with the PICTS method has shown that while the evaluated values of ionization energies are comparable using both methods, the PICTS technique gives systematically approximately two orders of magnitude higher capture cross sections than TEES.