{"id":{"repo_id":"strathclyde","oai_identifier":"oai:strathclyde:qb98mf474"},"canonical_url":"https://search.dev.ndltd.org/etd/strathclyde/oai:strathclyde:qb98mf474","repository":{"repo_id":"strathclyde","name":"University of Strathclyde","base_url":"https://stax.strath.ac.uk/catalog/oai"},"display":{"title":"Low-voltage organic transistors with high transconductance","abstract":"This thesis presents the development of low-voltage organic thin-film transistors with high transconductance. This was achieved by employing ultra-thin bi-layer gate dielectric consisting of aluminium oxide (AlOx) and a self-assembled monolayer of octadecyl phosphonic acid (C18PA) and by increasing the channel width of the transistors through the implementation of the multi-finger source/drain contacts. The transistors based on dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT) exhibited low turn-on voltage and a.c. transconductance around 30 to 60 µS. Transistor amplifiers based on such transistors exhibited voltage gain approaching 10 V/V and a gain of about 2 V/V when the supply voltage was limited to 5 V. Next, a series of [n]phenacenes ([n] = 5, 6, or 7) was used for the first time in combination with the thin AlOx/C18PA dielectric bi-layer. Regardless of the substrate and the source-drain contact geometry, the field-effect mobility of such transistors was found to increase with increasing length of the conjugated [n]phenacene core, leading to the best performance for [7]phenacene with the largest average field-effect mobility of 0.27 cm2/V⋅s for transistors on glass and 0.092 cm2/V⋅s for transistors on flexible PEN. The highest transconductance of 12.2 µS was achieved for [7]phenacene transistors on glass, which was lower than that achieved for DNTT transistors. In addition, nearly hysteresis-free behaviour, improved charge carrier injection/extraction properties, and reduced threshold voltage were achieved. Finally, a semi-empirical transistor model was developed in Matlab. The model was validated using d.c. and a.c. measurements obtained on DNTT transistors with high transconductance. Four fitting parameters were extracted by optimising a fitting function using genetic algorithm. The model reproduces the d.c. transistor measurements with high accuracy. The error between the measured and simulated peak-to-peak a.c. transconductance values ranged from 1.7% to 11.6%.","abstract_html":"This thesis presents the development of low-voltage organic thin-film transistors with high transconductance. This was achieved by employing ultra-thin bi-layer gate dielectric consisting of aluminium oxide (AlOx) and a self-assembled monolayer of octadecyl phosphonic acid (C18PA) and by increasing the channel width of the transistors through the implementation of the multi-finger source/drain contacts. The transistors based on dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT) exhibited low turn-on voltage and a.c. transconductance around 30 to 60 µS. Transistor amplifiers based on such transistors exhibited voltage gain approaching 10 V/V and a gain of about 2 V/V when the supply voltage was limited to 5 V. Next, a series of [n]phenacenes ([n] = 5, 6, or 7) was used for the first time in combination with the thin AlOx/C18PA dielectric bi-layer. Regardless of the substrate and the source-drain contact geometry, the field-effect mobility of such transistors was found to increase with increasing length of the conjugated [n]phenacene core, leading to the best performance for [7]phenacene with the largest average field-effect mobility of 0.27 cm2/V⋅s for transistors on glass and 0.092 cm2/V⋅s for transistors on flexible PEN. The highest transconductance of 12.2 µS was achieved for [7]phenacene transistors on glass, which was lower than that achieved for DNTT transistors. In addition, nearly hysteresis-free behaviour, improved charge carrier injection/extraction properties, and reduced threshold voltage were achieved. Finally, a semi-empirical transistor model was developed in Matlab. The model was validated using d.c. and a.c. measurements obtained on DNTT transistors with high transconductance. Four fitting parameters were extracted by optimising a fitting function using genetic algorithm. The model reproduces the d.c. transistor measurements with high accuracy. The error between the measured and simulated peak-to-peak a.c. transconductance values ranged from 1.7% to 11.6%.","abstract_has_math":false,"creators":["Al Ruzaiqi, Afra Salim Mohamed"],"institution":"University of Strathclyde","degree_name":"phd","degree_level":"doctoral-pg","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Soraghan, John","Gleskova, Helena"],"committee_chairs":[],"committee_members":[],"year":2020,"date_issued":"2020","date_published":"2020","updated_at":"2026-07-24T04:45:26Z","subjects":[],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier.doi","label":"DOI","values":["10.48730/hg32-5h92"],"render_values":[{"text":"10.48730/hg32-5h92","href":"https://doi.org/10.48730/hg32-5h92","code":true}]},{"key":"dc:identifier","label":"Identifier","values":["T15499"],"render_values":[{"text":"T15499","href":null,"code":true}]},{"key":"dc:creator.authoridentifier","label":"Author Identifier","values":["201656510"],"render_values":[{"text":"201656510","href":null,"code":true}]}]},"links":{"outbound_url":"https://stax.strath.ac.uk/concern/theses/qb98mf474","outbound_label":"Repository record","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Soraghan, John","Gleskova, Helena"]},{"key":"dc:creator","label":"Author","values":["Al Ruzaiqi, Afra Salim Mohamed"]},{"key":"dc:creator.authoridentifier","label":"Author Identifier","values":["201656510"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2020"]},{"key":"dc:date.issued","label":"Date","values":["2020"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Department of Electronic and Electrical Engineering"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Strathclyde"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["doctoral-pg"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["phd"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["T15499"]},{"key":"dc:identifier.doi","label":"DOI","values":["10.48730/hg32-5h92"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://stax.strath.ac.uk/concern/theses/qb98mf474"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["This thesis presents the development of low-voltage organic thin-film transistors with high transconductance. This was achieved by employing ultra-thin bi-layer gate dielectric consisting of aluminium oxide (AlOx) and a self-assembled monolayer of octadecyl phosphonic acid (C18PA) and by increasing the channel width of the transistors through the implementation of the multi-finger source/drain contacts. The transistors based on dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT) exhibited low turn-on voltage and a.c. transconductance around 30 to 60 µS. Transistor amplifiers based on such transistors exhibited voltage gain approaching 10 V/V and a gain of about 2 V/V when the supply voltage was limited to 5 V. Next, a series of [n]phenacenes ([n] = 5, 6, or 7) was used for the first time in combination with the thin AlOx/C18PA dielectric bi-layer. Regardless of the substrate and the source-drain contact geometry, the field-effect mobility of such transistors was found to increase with increasing length of the conjugated [n]phenacene core, leading to the best performance for [7]phenacene with the largest average field-effect mobility of 0.27 cm2/V⋅s for transistors on glass and 0.092 cm2/V⋅s for transistors on flexible PEN. The highest transconductance of 12.2 µS was achieved for [7]phenacene transistors on glass, which was lower than that achieved for DNTT transistors. In addition, nearly hysteresis-free behaviour, improved charge carrier injection/extraction properties, and reduced threshold voltage were achieved. Finally, a semi-empirical transistor model was developed in Matlab. The model was validated using d.c. and a.c. measurements obtained on DNTT transistors with high transconductance. Four fitting parameters were extracted by optimising a fitting function using genetic algorithm. The model reproduces the d.c. transistor measurements with high accuracy. The error between the measured and simulated peak-to-peak a.c. transconductance values ranged from 1.7% to 11.6%."]},{"key":"dc:description.abstract","label":"Abstract","values":["This thesis presents the development of low-voltage organic thin-film transistors with high transconductance. This was achieved by employing ultra-thin bi-layer gate dielectric consisting of aluminium oxide (AlOx) and a self-assembled monolayer of octadecyl phosphonic acid (C18PA) and by increasing the channel width of the transistors through the implementation of the multi-finger source/drain contacts. The transistors based on dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT) exhibited low turn-on voltage and a.c. transconductance around 30 to 60 µS. Transistor amplifiers based on such transistors exhibited voltage gain approaching 10 V/V and a gain of about 2 V/V when the supply voltage was limited to 5 V. Next, a series of [n]phenacenes ([n] = 5, 6, or 7) was used for the first time in combination with the thin AlOx/C18PA dielectric bi-layer. Regardless of the substrate and the source-drain contact geometry, the field-effect mobility of such transistors was found to increase with increasing length of the conjugated [n]phenacene core, leading to the best performance for [7]phenacene with the largest average field-effect mobility of 0.27 cm2/V⋅s for transistors on glass and 0.092 cm2/V⋅s for transistors on flexible PEN. The highest transconductance of 12.2 µS was achieved for [7]phenacene transistors on glass, which was lower than that achieved for DNTT transistors. In addition, nearly hysteresis-free behaviour, improved charge carrier injection/extraction properties, and reduced threshold voltage were achieved. Finally, a semi-empirical transistor model was developed in Matlab. The model was validated using d.c. and a.c. measurements obtained on DNTT transistors with high transconductance. Four fitting parameters were extracted by optimising a fitting function using genetic algorithm. The model reproduces the d.c. transistor measurements with high accuracy. The error between the measured and simulated peak-to-peak a.c. transconductance values ranged from 1.7% to 11.6%."]},{"key":"dc:title","label":"Title","values":["Low-voltage organic transistors with high transconductance"]}]}],"canonical_facts":{"dc:contributor.advisor":["Soraghan, John","Gleskova, Helena"],"dc:creator":["Al Ruzaiqi, Afra Salim Mohamed"],"dc:creator.authoridentifier":["201656510"],"dc:date":["2020"],"dc:date.issued":["2020"],"dc:description":["This thesis presents the development of low-voltage organic thin-film transistors with high transconductance. This was achieved by employing ultra-thin bi-layer gate dielectric consisting of aluminium oxide (AlOx) and a self-assembled monolayer of octadecyl phosphonic acid (C18PA) and by increasing the channel width of the transistors through the implementation of the multi-finger source/drain contacts. The transistors based on dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT) exhibited low turn-on voltage and a.c. transconductance around 30 to 60 µS. Transistor amplifiers based on such transistors exhibited voltage gain approaching 10 V/V and a gain of about 2 V/V when the supply voltage was limited to 5 V. Next, a series of [n]phenacenes ([n] = 5, 6, or 7) was used for the first time in combination with the thin AlOx/C18PA dielectric bi-layer. Regardless of the substrate and the source-drain contact geometry, the field-effect mobility of such transistors was found to increase with increasing length of the conjugated [n]phenacene core, leading to the best performance for [7]phenacene with the largest average field-effect mobility of 0.27 cm2/V⋅s for transistors on glass and 0.092 cm2/V⋅s for transistors on flexible PEN. The highest transconductance of 12.2 µS was achieved for [7]phenacene transistors on glass, which was lower than that achieved for DNTT transistors. In addition, nearly hysteresis-free behaviour, improved charge carrier injection/extraction properties, and reduced threshold voltage were achieved. Finally, a semi-empirical transistor model was developed in Matlab. The model was validated using d.c. and a.c. measurements obtained on DNTT transistors with high transconductance. Four fitting parameters were extracted by optimising a fitting function using genetic algorithm. The model reproduces the d.c. transistor measurements with high accuracy. The error between the measured and simulated peak-to-peak a.c. transconductance values ranged from 1.7% to 11.6%."],"dc:description.abstract":["This thesis presents the development of low-voltage organic thin-film transistors with high transconductance. This was achieved by employing ultra-thin bi-layer gate dielectric consisting of aluminium oxide (AlOx) and a self-assembled monolayer of octadecyl phosphonic acid (C18PA) and by increasing the channel width of the transistors through the implementation of the multi-finger source/drain contacts. The transistors based on dinaphtho[2,3-b:2',3'-f]thieno[3,2-b]thiophene (DNTT) exhibited low turn-on voltage and a.c. transconductance around 30 to 60 µS. Transistor amplifiers based on such transistors exhibited voltage gain approaching 10 V/V and a gain of about 2 V/V when the supply voltage was limited to 5 V. Next, a series of [n]phenacenes ([n] = 5, 6, or 7) was used for the first time in combination with the thin AlOx/C18PA dielectric bi-layer. Regardless of the substrate and the source-drain contact geometry, the field-effect mobility of such transistors was found to increase with increasing length of the conjugated [n]phenacene core, leading to the best performance for [7]phenacene with the largest average field-effect mobility of 0.27 cm2/V⋅s for transistors on glass and 0.092 cm2/V⋅s for transistors on flexible PEN. The highest transconductance of 12.2 µS was achieved for [7]phenacene transistors on glass, which was lower than that achieved for DNTT transistors. In addition, nearly hysteresis-free behaviour, improved charge carrier injection/extraction properties, and reduced threshold voltage were achieved. Finally, a semi-empirical transistor model was developed in Matlab. The model was validated using d.c. and a.c. measurements obtained on DNTT transistors with high transconductance. Four fitting parameters were extracted by optimising a fitting function using genetic algorithm. The model reproduces the d.c. transistor measurements with high accuracy. The error between the measured and simulated peak-to-peak a.c. transconductance values ranged from 1.7% to 11.6%."],"dc:identifier":["T15499"],"dc:identifier.doi":["10.48730/hg32-5h92"],"dc:identifier.uri":["https://stax.strath.ac.uk/concern/theses/qb98mf474"],"dc:publisher.department":["Department of Electronic and Electrical Engineering"],"dc:publisher.institution":["University of Strathclyde"],"dc:title":["Low-voltage organic transistors with high transconductance"],"dc:type.qualificationlevel":["doctoral-pg"],"dc:type.qualificationname":["phd"]},"updated_at":"2026-07-24T04:45:26Z"}