Preparation And Research Of P-N Junction Based On SnO₂

Transparent conducting oxides （TCOs） are widely used in a variety of applications such as frontsurface electrodes of solar cells and flat panel displays, low emissivity windows, touch-panel control,defrosting windows of aircraft, and static dissipation layer due to the characteristics of low resistivity andtransparency in the visible region. Research on the p-type transparent conductive oxide has graduallybecome one of the hot spots in recent years. However, most of the TCO films has been put into applicationand application are the n-type conductive film and p-type conductive film is seldom applied. As a moreappropriate candidate for p-type doped materials, SnO₂is suitable for practical applications.1. The Al-doped SnO₂transparent conductive thin films were deposited on the quartz glasssubstrates by magnetron sputtering using Al metal target and SnO₂ceramic target. The best condition forsputtering p-type SnO₂:Al thin films is that the substrate temperature is300℃. The sputtering time ofaluminum film is40s and incubated in470℃for4hours after the end of sputtering. In this experiment, thehighest hole concentration is5.854×10¹⁹(cm^-3) with the lowest resistivity is2.878×10^-2（Ω·cm） and hallmobility is2.721(cm²（V·sec）^-1).2. SnO₂: A1film has a tetragonal cassiterite structure, After annealing incubated for4h at atemperature of470℃, the average grain size of the film is13.16nm, smaller than before, grain density isincreased, The film surface becomes smooth and the surface roughness decreased. In addition, the averagetransmittance of films in visible region is high as80%.3. Sb-doped SnO₂transparent conductive thin films were deposited on quartz glass substrates useby magnetron sputtering. It has a tetragonal cassiterite structure. SnO₂: Sb film is very uniform, dense, smooth, constituted by columnar nano-particles, with better microstructure. After annealing incubated for4h at a temperature of550℃, it is observed that NiO films are highly crystalline in nature with preferredorientation along the （200）、（220） direction by using magnetron sputtering.4. p-n heterojunctions （p-NiO/n-SnO₂:Sb）and homojunctions（p-SnO₂:Al/n-SnO₂:Sb） wereassembled using the above prepared p-SnO₂/n-SnO₂and p-NiO thin films. They are highly crystalline innature and with better microstructure. The current-voltage （I-V） characteristics of homojunctions（p-SnO₂:Al/n-SnO₂:Sb） show the rectifying characteristics of typical p-n junctions. The open-circuitvoltage is3.77V. The average transmittance of films in visible region is72.4%. Lattice matching degree ofheterojunctions （p-NiO/n-SnO₂:Sb） is12.9%. The I-V curve of the heterojunction is nonlinear, showingvery good rectifying and the open circuit voltage of3.5V. The average transmittance of the heterojunctionin the visible range is81%.