Persistent positive and transient absolute negative photoconductivity observed in diamond photodetectors
Persistent positive and transient absolute negative photoconductivity observed in diamond photodetectors
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DOI：
10.1103/physrevb.78.045112
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发表时间：
2008-07-01
影响因子：
3.7
通讯作者：
Kleider, Jean-Paul
中科院分区：
文献类型：
--
作者：
Liao, Meiyong;Koide, Yasuo;Kleider, Jean-Paul
研究了生长在Ib（100）型衬底上的掺硼同质外延金刚石薄膜的持续光电导和光猝灭现象。在深紫外光照射下，硼掺杂诱导了正的持续光电导（PPPC）和光电流增益。从热刺激电流测量的结果推断出具有约1.37 eV的热能的深缺陷。光学猝灭实验揭示了约2eV的阈值光子能量。深缺陷的热能和光能之间的差异表明大的晶格弛豫。光猝灭PPPC后，在DUV光照射下，在零电场或弱电场下观察到绝对瞬态负光电流（TNPC）。绝对TNPC是由于在基板中的带电氮的瞬态电子填充。衬底中的氮和外延层中的硼相关缺陷的组合显然是PPPC和TNPC效应的原因。因此，沉积在Ib型金刚石衬底上的薄外延层的整体光响应特性可以通过调节衬底中的氮浓度和外延层中的硼浓度来定制。
Persistent photoconductivity and optical quenching phenomena in boron-doped homoepitaxial diamond thin films grown on type Ib (100) substrates were investigated. Boron doping induced positive persistent photoconductivity (PPPC) and photocurrent gain upon the illumination of deep ultraviolet (DUV) light. A deep defect with a thermal energy of around 1.37 eV was deduced from the results of thermally stimulated current measurements. An optical quenching experiment revealed a threshold photon energy of around 2 eV. The difference between the thermal and optical energies of the deep defect suggests a large lattice relaxation. An absolute transient negative photocurrent (TNPC) was observed for zero or weak electric fields with DUV light illumination after optically quenching the PPPC. The absolute TNPC was due to transient electron filling of the charged nitrogen in the substrate. The combination of the nitrogen in the substrate and the boron-related defects in the epilayer was apparently responsible for the PPPC and TNPC effects. Therefore, the overall photoresponse properties of a thin epilayer deposited on a type Ib diamond substrate can be tailored by adjusting the concentration of nitrogen in the substrate and of boron in the epilayer.