抚仙湖太阳观测和研究基地知识库

采用分子束外延技术,在GaSb衬底上生长了pin结构的InAs(8ML)/GaSb(8ML)超晶格中波红外光电二极管.用阳极硫化和ZnS薄膜对二极管表面进行钝化处理后,二极管漏电流密度降低了三个数量级,零偏阻抗R0达到106Ω,R0A达到103Ωcm2.通过测量电流密度与光敏元周长面积比的关系可知表面漏电不是主要漏电成分;电容电压特性曲线表明吸收层i层背景掺杂浓度约4~5×1014cm-3.在空气中放置一个月后再次测试,发现响应率和探测率几乎没有变化.与化学硫化和SiO2薄膜钝化方法相比,阳极硫化方法是一种更简单和有效的钝化方法.

InAs(8ML)/GaSb(8ML) superlattice with p-i-n structure was grown on GaSb substrates by molecular beam epitaxy. The mid-wavelength infrared photodiodes with different area mesa was fabricated through standard photolithography, wet chemical etching and sputtered metal contacts. The passivation was finished by the anode sulphur technique and sputtered ZnS thin film. Compared with (NH4)2S solution treatment, the surface leackage currents density decreased three orders of magnitude and the R0A increased up to 103 times. The zero-bias resistance R0 was measured up to 106 ohms. The surface leakage current was not major dark current in photodiodes after the anode sulfur passivation. Capacitance-voltage relation showed that the background concentration in i layer was about 4~5×1014 cm-3. The property of the photodiode appeared no degradation after exposured in air for one month. It verified that anode sulphur passivation is an easy and effective technique.