ZnO/P-Si异质结的光电特性研究

利用脉冲激光沉积方法在P-Si(100)衬底上生长ZnO薄膜,制备ZnO/P-Si异质结,研究衬底温度对异质结光电特性的影响.结果表明,在400℃,500℃,550℃和600℃下生长ZnO制备的异质结都有一定的整流特性,反向暗电流随着衬底温度的升高略有增加,在550℃下制备的样品具有最明显的光电效应.ZnO/P-Si异质结对可见光和紫外光呈现出不同的响应性.在可见光照射下,光电流随反向偏压急剧增大,偏压增大到某一值时,光电流增速变小,而在紫外光下,光电流有逐渐增大的趋势.根据ZnO的透射谱认为,可见光和紫外光是异质结不同的耗尽区诱导电子-空穴对产生光电流的.

Photoelectric Effects of ZnO/P-Si Heterojunction

ZnO/P-Si heterojunctions are fabricated by pulsed laser deposition of ZnO films on P-Si substrates. The substrate temperatures of 400 ℃, 500 ℃, 550 ℃ and 600 ℃ are taken for the ZnO film deposition. All the heterojunctions show typical rectifying behaviors and the reverse dark current increases with the substrate temperature. The sample prepared at 550 ℃ shows the best photoelectric effects. There are different Ⅰ-Ⅴ characteristics as the ZnO/P-Si heterojunction is exposed to visible and ultraviolet (UV) photons. The photocurrent increases rapidly in the initial several voltages, but slowly beyond a certain reverse bias voltage. When the sample is illuminated by UV photon, the photocurrents show a gradual increase with the bias. According to the transmittance spectra of the ZnO films, it is thought that the electron-hole pairs are induced in the different depletion of the heterojunction for the visible and UV photons.