Room-temperature violet luminescence and ultraviolet photodetection of Sb-doped ZnO/Al-doped ZnO homojunction array
1 Department of Physics, National Taiwan University, Taipei 106, Taiwan
2 Graduate Institute of Applied Physics, National Taiwan University, Taipei 106, Taiwan
3 Department of Materials and Optoelectronic Science, National Sun Yat-sen University, Kaohsiung 804, Taiwan
4 Center for Nanoscience and Nanotechnology, National Sun Yat-sen University, Kaohsiung 804, Taiwan
5 School of Electronic and Electrical Engineering, Sungkyunkwan University, Suwon 440-746, South Korea
Nanoscale Research Letters 2013, 8:313 doi:10.1186/1556-276X-8-313Published: 5 July 2013
A Sb-doped ZnO microrod array was fabricated on an Al-doped ZnO thin film by electrodeposition. Strong violet luminescence, originated from free electron-to-acceptor level transitions, was identified by temperature-dependent photoluminescence measurements. This acceptor-related transition was attributed to substitution of Sb dopants for Zn sites, instead of O sites, to form a complex with two Zn vacancies (VZn), the SbZn-2VZn complex. This SbZn-2VZn complex has a lower formation energy and acts as a shallow acceptor which can induce the observed strong violet luminescence. The photoresponsivity of our ZnO p-n homojunction device under a negative bias demonstrated a nearly 40-fold current gain, illustrating that our device is potentially an excellent candidate for photodetector applications in the ultraviolet wavelength region.