ZnO∶Al/p-Si的接触特性

利用射频磁控溅射制备了ZnO∶A l/p-S i接触,并对其进行C-V和I-V特性的77~350 K变温测量。并对未热退火和800℃热退火两种样品的测量结果进行了对比分析。结果发现,未经热退火和经过热退火处理的样品在C-V和I-V特性上有很大差别。解释了两种样品的C-V和I-V测量结果的不同。对于未退火的样品,由于界面处的大量界面态的屏蔽作用,使得ZnO∶A l/p-S i异质结的C-V曲线发生畸变。经800℃热退火,ZnO∶A l/p-S i异质结的C-V特性恢复正常,说明热退火已经消除了异质结中的界面态和缺陷态。研究表明ZnO∶A l/p-S i异质结经适当热退火处理有更好的整流特性同时对光致发光也更有利。     

ZnO:Al/p-Si的接触特性

利用射频磁控溅射制备了ZnO：Al／p—Si接触,并对其进行C-V和I-V特性的77～350K变温测量。并对未热退火和800℃热退火两种样品的测量结果进行了对比分析。结果发现,未经热退火和经过热退火处理的样品在C—V和I-V特性上有很大差别。解释了两种样品的C—V和I-V测量结果的不同。对于未退火的样品,由于界面处的大量界面态的屏蔽作用,使得ZnO：Al／p—Si异质结的C—V曲线发生畸变。经800℃热退火,ZnO：Al／p—Si异质结的C—V特性恢复正常,说明热退火已经消除了异质结中的界面态和缺陷态。研究表明ZnO：Al／p—Si异质结经适当热退火处理有更好的整流特性同时对光致发光也更有利。     

Effects of Grain Boundary Barrier in ZnO/Si Heterostructure

The influence of ZnO microstructure on electrical barriers is investigated using capacitance-voltage （C - V）, current-voltage （I- V） and deep level transient spectroscopy （DLTS） measurements. A deep level center located at Ec - 0.24 eV obtained by DLTS in the ZnO films is an intrinsic defect related to Zni. The surface states in the ZnO grains that have acceptor behavior of capturing electrons from Zni defects result in the formation of grain barriers. In addition, we find that the current transport is dominated by grain barriers after annealing at 600℃ at 02 ambient. With the increment of the annealing temperature, the current transport mechanism of ZnO/Si heterostructure is mainly dominated by thermo-emission.     

ZnO薄膜微结构变化对光电特性的影响

使用脉冲激光淀积(PLD)技术在n型Si衬底上沉积氧化锌(ZnO)薄膜,在O2气氛下对样品进行了500℃(Sample1,S1),600℃(Sample2,S2),700℃(Sample3,S3)和800℃(Sample4,S4)退火,随后进行了X射线衍射(XRD)谱,椭偏光折射率,热激电流(TSC)和电容-电压(C-V)的测量。研究发现:S1中晶界的电子陷阱由高浓度的深能级杂质(Zni)提供的电子填充,该能级位于ET=EC-0.24±0.08eV。S3中出现与中性施主(D0)有关的深能级中心,其ET=EC-0.13±0.03eV,推测D0的出现与高温氧气条件退火下晶界处形成的复合体缺陷有关。XRD和椭偏光折射率测量结果表明:氧气对ZnO薄膜微结构的修饰是改变ZnO/Si结构光电特性的主要因素。     

Electrical and deep levels characteristics of ZnO/Si heterostructure by MOCVD deposition

ZnO films have been prepared on p-type Si substrates by metal-organic chemical vapour deposition （MOCVD） at different total gas flow rates. The current versus voltage and temperature （I - V - T） characteristics, the deep-level transient spectroscopy （DLTS） and the photoluminescence （PL） spectra of the samples were measured. DLTS shows two deep-level centres of E1 （Ec-0.13±0.02eV） and E2 （Ec-0.43±0.05eV） in sample 1202a, which has a ZnO/p-Si heterostructure. A deep level at Ec-0.13±0.01 eV was also obtained from the I -T characteristics. It was considered to be the same as E1 obtained from DLTS measurement. The emission related to this deep level center was detected by PL spectra. In addition, the energy location and the relative trap density of E1 was varied when the total gas flow rate was changed.