| 학회 | 한국재료학회 |
| 학술대회 | 2008년 가을 (11/07 ~ 11/07, 차세대융합기술연구원) |
| 권호 | 14권 2호 |
| 발표분야 | 반도체재료 |
| 제목 | Fabrication and characterization of n-ZnO:Ga/p-Si heterojunction light emitting diodes using SiO2 current-blocking layer |
| 초록 | ZnO has been attractive for optoelectronic applications such as blue and ultraviolet (UV) light emitting diodes (LEDs) and detectors, because it has superior advantages over GaN. The notable properties of ZnO are its wide band gap (3.37 eV) and a large exciton binding energy (~60 meV) which is much higher than GaN (~21 meV). However, the fabrication of efficient light emitting devices using ZnO homojunctions is very difficult due to the lack of reproducibility of the p-type ZnO with high hall concentration and mobility. Thus, the ZnO-based p-n heterojunction LEDs would be expected to exhibit improved device performance compared to the homojunction LEDs. Several heterojunctions such as n-ZnO/p-Si, n-ZnO/p-GaN, n-ZnO/p-Cu2O, and n-ZnO/p-SiC accomplishing the electroluminescence (EL) of the ZnO have been reported.1 Among these heterojunctions, the n-ZnO/p-Si heterostructure is a good candidate for ZnO-based heterojunction LEDs because of its competitive price and lower driving voltage. However, the conventional LED shows much lower extraction efficiency, because it has small top contact and large backside contact. In this structure, the injected current from the top contact enters the active region underneath the top contact. Thus, the emitted light is hindered by the opaque top contact. This problem can be solved by using a current-blocking layer that prevents the current injection into the active region below the top contact. In this work, the ZnO:Ga film was grown on the SiO2-patterned p-Si (100) substrates using RF magnetron sputtering method. The SiO2-patterned layer was deposited to realize the effect of current-blocking layers. At the same time, the normal p-Si wafer was used as the substrate for deposition of ZnO:Ga film in order to compare with the LED of ZnO:Ga/p-Si structure using SiO2 current-blocking layer. The crystal structure of ZnO:Ga films was characterized by x-ray diffraction. Photoluminescence measurements were carried out using a He-Cd laser (325 nm) as the excitation source. The properties of the LEDs were investigated by current-voltage and electroluminescence characteristics. |
| 저자 | 한원석1, 김영이1, 안철현1, 김동찬1, 공보현1, 조형균1, 이종훈2, 김홍승2 |
| 소속 | 1성균관대, 2한국해양대 |
| 키워드 | current-blocking layer; ZnO; LED; sputtering |
