Using Flexible Polyimide as a Substrate to Deposit ZnO:Ga Thin Films and Fabricate p-i-n -Si:H Thin-Film Solar Cells

Abstract

The GZO thin films were deposited on the polyimide (PI) substrates to investigate their properties for the possibly flexible applications. The effects of substrate temperature (from room temperature to 200&#xb0;C) on the surface and cross-session morphologies, X-ray diffraction pattern, optical transmission spectrum, carrier concentration, carrier mobility, and resistivity of the GZO thin films on PI substrates were studied. The measured results showed that the substrate temperature had large effect on the characteristics of the GZO thin films. The cross-section observations really indicated that the GZO thin films deposited at 200&#xb0;C and below had different crystalline structures. The value variations in the films&#x2019; optical band gap (<svg style="vertical-align:-5.76988pt;width:18.262501px;" id="M2" height="18.362499" version="1.1" viewBox="0 0 18.262501 18.362499" width="18.262501" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"> <g transform="matrix(.017,-0,0,-.017,.062,11.113)"><path id="x1D438" d="M609 650l-19 -162l-30 -2q2 69 -14 94q-9 18 -28.5 26t-74.5 8h-88q-30 0 -37 -6.5t-12 -36.5l-41 -212h103q48 0 69 5.5t32 19t26 50.5h29l-40 -198h-30q2 58 -11.5 70.5t-85.5 12.5h-99l-30 -167q-17 -87 3 -101q18 -15 111 -15q59 0 89 7t54 27q8 7 15.5 16t16 21.5&#xA;l14 20.5t15 23.5t13.5 21.5l29 -10q-52 -129 -71 -163h-500l6 28q66 4 83 17.5t28 73.5l77 409q11 61 -0.5 75.5t-78.5 18.5l10 28h467z" /></g> <g transform="matrix(.012,-0,0,-.012,10.8,15.188)"><path id="x1D454" d="M546 430q-14 -33 -37.5 -140t-38.5 -209q-29 -195 -156 -289q-29 -21 -70 -37t-78 -16q-62 0 -102.5 37t-40.5 69q0 27 26 48q19 15 25 -3q13 -43 46.5 -69t87.5 -26q55 0 83 21q29 22 50 65t43 140q14 64 29 163h-2q-55 -81 -149 -152q-59 -44 -102 -44q-23 0 -43.5 30&#xA;t-20.5 85q0 74 32.5 145.5t84.5 117.5q40 35 100 58.5t117 23.5q21 0 65 -8q30 -6 44 -6zM456 386q-40 16 -81 16q-29 0 -64 -13q-42 -17 -85 -97q-19 -36 -31.5 -86t-12.5 -86q0 -64 30 -64q20 0 52.5 21t60.5 52q74 81 95 123q26 62 36 134z" /></g> </svg>) of the GZO thin films were evaluated from plots of<svg style="vertical-align:-5.76988pt;width:142.925px;" id="M3" height="23.025" version="1.1" viewBox="0 0 142.925 23.025" width="142.925" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"> <g transform="matrix(.017,-0,0,-.017,5.725,15.775)"><path id="x28" d="M300 -147l-18 -23q-106 71 -159 185.5t-53 254.5v1q0 139 53 252.5t159 186.5l18 -24q-74 -62 -115.5 -173.5t-41.5 -242.5q0 -130 41.5 -242.5t115.5 -174.5z" /></g><g transform="matrix(.017,-0,0,-.017,11.607,15.775)"><use xlink:href="#x1D6FC"/></g><g transform="matrix(.017,-0,0,-.017,21.262,15.775)"><path id="x210E" d="M499 88q-41 -46 -83.5 -73t-68.5 -27q-41 0 -19 98l52 225q10 43 8 59.5t-16 16.5q-37 0 -112 -65t-117 -135q-14 -42 -38 -179q-36 -7 -75 -20l-7 8l127 594q8 40 2.5 49t-35.5 9h-35l5 25q36 3 71.5 13t56.5 18t25 8q11 0 3 -38l-88 -417h2q77 102 195 167q44 24 79 24&#xA;q61 0 30 -130l-52 -220q-8 -33 4 -33q8 0 31 14.5t43 33.5z" /></g><g transform="matrix(.017,-0,0,-.017,30.033,15.775)"><path id="x1D708" d="M509 373q0 -52 -42.5 -118.5t-124.5 -159.5l-94 -107h-27q-22 209 -78 342q-21 48 -41 48q-18 0 -63 -62l-22 21q77 111 125 111q30 0 52 -21.5t38 -75.5q37 -130 52 -285q48 62 74.5 99.5t53.5 87t27 76.5q0 43 -17 60q-5 5 -5 15q0 17 12.5 30.5t28.5 13.5&#xA;q21 0 36 -22.5t15 -52.5z" /></g><g transform="matrix(.017,-0,0,-.017,39.077,15.775)"><path id="x29" d="M275 270q0 -296 -211 -440l-19 23q75 62 116.5 174t41.5 243t-42 243t-116 173l19 24q211 -144 211 -440z" /></g> <g transform="matrix(.012,-0,0,-.012,44.962,7.613)"><path id="x32" d="M412 140l28 -9q0 -2 -35 -131h-373v23q112 112 161 170q59 70 92 127t33 115q0 63 -31 98t-86 35q-75 0 -137 -93l-22 20l57 81q55 59 135 59q69 0 118.5 -46.5t49.5 -122.5q0 -62 -29.5 -114t-102.5 -130l-141 -149h186q42 0 58.5 10.5t38.5 56.5z" /></g> <g transform="matrix(.017,-0,0,-.017,56.012,15.775)"><path id="x3D" d="M535 323h-483v50h483v-50zM535 138h-483v50h483v-50z" /></g><g transform="matrix(.017,-0,0,-.017,70.716,15.775)"><path id="x1D450" d="M383 397q0 -32 -35 -49q-12 -6 -23 8q-37 45 -84 45t-90 -71q-40 -65 -40 -167q0 -57 22 -86t59 -29q38 0 81.5 24.5t69.5 51.5l16 -21q-44 -53 -104 -84t-109 -31q-56 0 -89.5 41t-33.5 117q0 61 30 124t79 105q33 28 81 50.5t86 22.5q34 0 59 -15.5t25 -35.5z" /></g><g transform="matrix(.017,-0,0,-.017,77.618,15.775)"><use xlink:href="#x28"/></g><g transform="matrix(.017,-0,0,-.017,83.499,15.775)"><use xlink:href="#x210E"/></g><g transform="matrix(.017,-0,0,-.017,92.271,15.775)"><use xlink:href="#x1D708"/></g><g transform="matrix(.017,-0,0,-.017,105.088,15.775)"><path id="x2212" d="M535 230h-483v50h483v-50z" /></g><g transform="matrix(.017,-0,0,-.017,118.84,15.775)"><use xlink:href="#x1D438"/></g> <g transform="matrix(.012,-0,0,-.012,129.588,19.862)"><use xlink:href="#x1D454"/></g> <g transform="matrix(.017,-0,0,-.017,136.988,15.775)"><use xlink:href="#x29"/></g> </svg>, revealing that the measured <svg style="vertical-align:-5.76988pt;width:18.262501px;" id="M4" height="18.362499" version="1.1" viewBox="0 0 18.262501 18.362499" width="18.262501" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"> <g transform="matrix(.017,-0,0,-.017,.062,11.113)"><use xlink:href="#x1D438"/></g> <g transform="matrix(.012,-0,0,-.012,10.8,15.188)"><use xlink:href="#x1D454"/></g> </svg> values increased with increasing deposition temperature. Finally, the prepared GZO thin films were also used as the transparent electrodes to fabricate the <svg style="vertical-align:-0.1638pt;width:9.7749996px;" id="M5" height="7.9499998" version="1.1" viewBox="0 0 9.7749996 7.9499998" width="9.7749996" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"> <g transform="matrix(.017,-0,0,-.017,.062,7.675)"><use xlink:href="#x1D6FC"/></g> </svg>-Si amorphous silicon thin-film solar cells on the flexible PI substrates, and the properties of which were also measured. We would also prove that substrate temperature of the GZO thin films had large effect on the characteristics of the fabricated <svg style="vertical-align:-0.1638pt;width:9.7749996px;" id="M6" height="7.9499998" version="1.1" viewBox="0 0 9.7749996 7.9499998" width="9.7749996" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://www.w3.org/2000/svg"> <g transform="matrix(.017,-0,0,-.017,.062,7.675)"><use xlink:href="#x1D6FC"/></g> </svg>-Si amorphous silicon thin-film solar cells.