Electroluminescent and transport mechanisms of n-ZnO∕p-Si heterojunctions

The distinct visible electroluminescence (EL) at room temperature has been realized based on n-ZnO∕p-Si heterojunction. The EL peak energy coincided well with the deep-level photoluminescence of ZnO, suggesting that the EL emission was originated from the radiative recombination via deep-level defects in n-ZnO layers. The transport mechanisms of the diodes have been discussed with the characteristics of current-voltage (I-V) and light-output–voltage (L-V), in terms of the energy band diagram of ZnO∕Si heterojunction. The tunneling mechanism via deep-level states was the main conduction process at low forward bias, while space-charge-limited current conduction dominated the carrier transport at higher bias. Light-output–current (L-I) characteristic of the diode followed a power law such as L∼Im, which showed a superlinear behavior at low injection current and became almost linear due to the saturation of nonradiative recombination centers at high current level.

[1]  David C. Look,et al.  Fabrication and characterization of n-ZnO/p-AlGaN heterojunction light-emitting diodes on 6H-SiC substrates , 2003 .

[2]  H. Ohta,et al.  Fabrication and characterization of ultraviolet-emitting diodes composed of transparent p-n heterojunction, p-SrCu2O2 and n-ZnO , 2001 .

[3]  H. Sigmund,et al.  Analysis of the current-voltage characteristic of solar cells , 1986 .

[4]  D. G. Baik,et al.  Application of sol-gel derived films for ZnO/n-Si junction solar cells , 1999 .

[5]  S. Im,et al.  Ultraviolet-enhanced photodiode employing n-ZnO/p-Si structure , 2003 .

[6]  Ignacio Mártil,et al.  Influence of defects on the electrical and optical characteristics of blue light-emitting diodes based on III–V nitrides , 1997 .

[7]  Chung Yin Kwong,et al.  Photoluminescence and Electron Paramagnetic Resonance of ZnO Tetrapod Structures , 2004 .

[8]  H. Ohno,et al.  Blue Light-Emitting Diode Based on ZnO , 2005, cond-mat/0504587.

[9]  W. Park,et al.  Electroluminescence in n‐ZnO Nanorod Arrays Vertically Grown on p‐GaN , 2004 .

[10]  J. Y. Lee,et al.  Photoresponse characteristics of n-ZnO/p-Si heterojunction photodiodes , 2002 .

[11]  R. Zhang,et al.  Blue-yellow ZnO homostructural light-emitting diode realized by metalorganic chemical vapor deposition technique , 2006 .

[12]  Rusli,et al.  Fabrication of n-ZnO:Al∕p-SiC(4H) heterojunction light-emitting diodes by filtered cathodic vacuum arc technique , 2005 .

[13]  D. Look,et al.  Observation of 430 nm Electroluminescence from ZnO/GaN Heterojunction Light-Emitting Diodes , 2003 .

[14]  David C. Look,et al.  The Future Of ZnO Light Emitters , 2004 .

[15]  Rong Zhang,et al.  Raman and photoluminescence of ZnO films deposited on Si (111) using low-pressure metalorganic chemical vapor deposition , 2003 .

[16]  John F. Muth,et al.  Dominance of tunneling current and band filling in InGaN/AlGaN double heterostructure blue light‐emitting diodes , 1996 .

[17]  David C. Look,et al.  Degenerate layer at GaN/sapphire interface: Influence on Hall-effect measurements , 1997 .

[18]  F. Namavar,et al.  Current injection mechanism for porous‐silicon transparent surface light‐emitting diodes , 1992 .

[19]  R. Zhang,et al.  Substrate temperature dependence of properties of ZnO thin films deposited by LP-MOCVD , 2004 .

[20]  Toru Aoki,et al.  ZnO diode fabricated by excimer-laser doping , 2000 .

[21]  E. Monroy,et al.  Analysis of the Visible and UV Electroluminescence in Homojunction GaN LED's , 1998 .

[22]  Shulin Gu,et al.  THE GROWTH AND ANNEALING OF SINGLE CRYSTALLINE ZNO FILMS BY LOW-PRESSURE MOCVD , 2002 .

[23]  Ishwara B. Bhat,et al.  Electrical characteristics of magnesium-doped gallium nitride junction diodes , 1998 .