第24卷第6期 2009年11月
文章编号：1000-324X(2009)06-1259-04
无机材料学报
Joumal of Inorganic Materials
Vol.24, No.6 Nov.,2009
DOI; 10.3724/SP.J.1077.2009.09217
A TransparentPN Junction Based on Tin-antimony Oxide Films JI Zhen-Guo'.2, ZHOU Rong-Fu', MAO Qi-Nan', HUO Li-Juan', CAO Hong
(1. Institute of Electronie Information, Hangzhou Dianzi University, Hangzhou 310018, China; 2. State Key Laboratory for Sil-icon Materials, Zhejiang University, Hangzhou 310027, China)
Abstract: Transparent and semiconductive tin-antimony oxide (TAO) films were fabricated by reactive DC magnetron sputte-ring, According to the results of Hall effect measurement, TAO films are p-type for Sn/Sb atomic ratio in the range of 0. 22-0. 33, while TAO films with Sn/Sb atomic ratio out of this range are n-type, Optical band-gap measurement results show that the bend-gap of all TAO films with various Sn/Sb ratios is almost identical ( ~3. 91eV). Finally, a PN junction based on n-TAO and p-TAO was fabricated using ITO as the electrode for n-TAO and a thin layer of Cu as the electrode for p-TCO. It shows typical rectifying characteristics of a homo-junction diode since both types of TAO films have almost the same band-gap values.
Key words: transparent semiconductive films; antimony-tin oxide; PN junction
Transparent electronics is an emerging electronic technology which employs wide band-gap semiconductors that are transparent in the visible region for the fabrica-tion of electronic and electro-optical devices[i-5], Until now, most wide band-gap materials used in transparent electronic devices are transparent conducting oxides films(TCOs). In most cases, transparent electronic devices studied are based on field effect transistors, rather than PN junctions, due to the lack of high quality p-type TCOs. Although progress is making in p-type TCOs by techniques such as co-doping, the electrical and optical characteristics of the p-type TCOs are still not as good as n-type TCOs 16a1], On the other hand, although the electrical behaviors of p-type TCOs are not as good as most n-type TCOs, the conductivity of the p-type TCOs is high enough to fabricate transparent PN junctions and other transparent electronic devices.
In a previous paper, we reported a new kind of transparent bipolar conductive oxide films consisting of tin-antimony oxide (TAO) (19), It is found that when ox-idized at 400°C, the TAO films show p-type conduction with Sn/Sb atomic ratios in the intermediated range(0. 22 0. 33), while they are n-type with Sn/Sb atom-ic ratios out of this range. In this paper, a PN junction consisting of p-type and n-type TAO films was fabricated which show clearly typical rectifying characteristics of PN junctions.
Experimental details
The PN junction of TAO was prepared as follows. Commercial ITO (indium tin oxide) glass was used as the back electrode and substrate, then a thin layer of about 300nm n-type TAO (Sn/Sb atomic ratio of 0.5) and a thin layer of p-type TAO ( Sn/Sb atomic ratio of 0. 33) with the same thickness were deposited on the ITO glass successively by reactive DC sputtering. Finally a thin layer of semi-transparent Cu was thermally evapo-rated as the top electrode, since no heavily doped p*-TCO is available yet. The detail of the deposition and characterization of the TAO films have been ex-plained in the reference [19]. The schematic structure of PN junction is shown in Fig. 1.
Cu
p-TAO
n-TAO
ITO Glas
Fig 1 Schematic structure of the PN junction based on TAO films
Received date:2009-03-31, Modified date:2009-06-17, Published onlline:2009-06-30
National Natural Scienoe Fund of China (60576063) : Science and Technology Project of Zhejisng Prowince (2008F70015)
Foundation item:
Biography: JI Zhen-Cuo( 1961 ), male, proiessor, E-mail: jisg2@ sju, edu. cn, jizg@ bdu. edu. cn 万方数据