Gity Farzan, Daly Aidan, Snyder Bradley, Peters Frank H, Hayes John, Colinge Cindy, Morrison Alan P, Corbett Brian
Tyndall National Institute, Lee Maltings, Dyke Parade, Cork, Ireland.
Opt Express. 2013 Jul 15;21(14):17309-14. doi: 10.1364/OE.21.017309.
We report on the photoresponse of an asymmetrically doped p(-)-Ge/n(+)-Si heterojunction photodiode fabricated by wafer bonding. Responsivities in excess of 1 A/W at 1.55 μm are measured with a 5.4 μm thick Ge layer under surface-normal illumination. Capacitance-voltage measurements show that the interfacial band structure is dependent on both temperature and light level, moving from depletion of holes at -50 °C to accumulation at 20 °C. Interface traps filled by photo-generated and thermally-generated carriers are shown to play a crucial role. Their filling alters the potential barrier height at the interface leading to increased flow of dark current and the above unity responsivity.
我们报道了通过晶圆键合制造的非对称掺杂p(-)-Ge/n(+)-Si异质结光电二极管的光响应。在垂直表面照明下，对于厚度为5.4μm的Ge层，在1.55μm处测量到的响应度超过1 A/W。电容-电压测量表明，界面能带结构取决于温度和光照水平，从-50°C时的空穴耗尽状态转变为20°C时的积累状态。结果表明，由光生载流子和热生载流子填充的界面陷阱起着关键作用。它们的填充改变了界面处的势垒高度，导致暗电流增加以及响应度超过单位值。
